JP4774721B2 - Low melting glass, sealing composition and sealing paste - Google Patents

Description

  The present invention relates to a sealing composition, and particularly contains substantially no lead component, and is used for a flat display such as a plasma display panel (hereinafter referred to as PDP). The simple “%” notation used in this specification means “% by mass”.

Conventionally, a sealing composition typified by an outer peripheral seal of a PDP is generally a lead-based material composed of a lead-based glass powder such as PbO—SiO ₂ —B ₂ O ₃ and a filler such as a refractory ceramic powder. However, in recent years, development of a composition that can be sealed at a low temperature without containing a lead component has been demanded from an environmental viewpoint.

  Known low-melting glasses not containing lead include phosphate glass, borophosphate glass, vanadium borate glass, alkali silicate glass, and bismuth glass. Among them, bismuth-based glass has attracted attention because it can be fired at a low temperature and has excellent chemical durability.

The bismuth-based glass that has been developed so far has a thermal expansion coefficient of 90 to 110 × 10 ⁻⁷ / ° C., and the thermal expansion coefficient of the glass used for the display (70 to 80 × 10 ⁻⁷ / ° C.). In order to match, a low expansion refractory ceramic filler was blended.

However, if the amount of ZnO contained in the low melting point glass component in the bismuth glass is small, the thermal expansion coefficient is as large as 110 × 10 ⁻⁷ / ° C. or more, and in order to lower this, a larger amount of refractory ceramic filler is blended. There was a problem that the viscosity of the material increased and sealing could not be performed at less than 500 ° C. (Patent Document 1).

Conversely, a low melting point glass containing a large amount of ZnO has also been developed, but the chemical durability of the low melting point glass is lowered because the content of Bi ₂ O ₃ is large and Al ₂ O ₃ is not contained. There was also a problem (Patent Document 2).

  On the other hand, the sealing member formed by pasting the sealing composition in the production of the PDP suppresses the generation of bubbles due to excessive flow of the sealing portion. Further, the sealing member is applied to other members such as ribs, phosphors and electrodes. In order to suppress thermal damage, the sealing temperature was baked at 500 ° C. or lower (preferably 480 ° C. or lower). However, these other members are also manufactured by a baking process in the same manner as the sealing of the sealing member, and there has been a problem that if the baking is performed individually, the process becomes longer and the manufacturing cost increases. In recent years, as a countermeasure, a plurality of members are simultaneously fired to shorten the process, and the seal member is also degreased and pre-baked (hereinafter referred to as pre-baking) in combination with these members. .

Therefore, the sealing temperature of the sealing member needs to be lower than the firing temperature of other members such as ribs, phosphors and electrodes for the above reasons. The firing temperature of these other members (= temporary firing temperature of the seal member) varies depending on each member, but is in the range of 450 to 550 ° C. in consideration of the recent demand for lowering the temperature. As a result, the sealing temperature of the sealing member is lower than the pre-baking temperature, and low melting point glass that can be sealed without impairing fluidity even by such a method of use has begun to be demanded. The conventional lead-based glass has a wide sealing temperature range (when the low-melting glass is used as an amorphous glass, it means a temperature range in which the low-melting glass can be sealed without crystallization). The above required characteristics were satisfied.
However, this bismuth-based glass has a narrow sealing temperature range even if it can be sealed at a low temperature. If the pre-baking temperature exceeds this sealing possible temperature range, it is included in Bi ₂ O ₃ and its glass component. B ₂ O ₃ , ZnO, etc. are prone to crystal formation and cannot be sealed at the sealing temperature during the main firing.

Furthermore, for mass production, it is preferable to melt in a continuous melting furnace that continuously performs the process from charging of raw materials to molding. In general, bismuth-based glass, like lead-based glass, needs to be melted by heating to 1000 ° C or higher in order to obtain homogeneous glass. Due to its strong erodibility, there was a problem that the amount of melted material (for example, alkali metal, zirconia, etc.) from the brick surface increased, which became the crystal nucleus of the glass and caused crystallization of the glass during temporary firing. In addition, since this glass has a very low viscosity during melting and a low surface tension, there was a problem that the glass leaked from the joint part of the brick that spread due to erosion during operation, and the glass could not be melted stably for a long time. .
Japanese Patent Laid-Open No. 9-278483 Japanese Patent Laid-Open No. 10-139478

  As described above, along with the shortening of the manufacturing process, the sealing member has been heated to a temperature exceeding the temperature for originally performing sealing at the stage of temporary firing. Conventional lead-based materials can be sealed at a temperature lower than the pre-baking temperature in the next baking after pre-baking. However, as for the bismuth glass developed so far, a glass that can be sealed at a temperature lower than the pre-baking temperature has not been found particularly in a flat display such as PDP.

  In addition, it is a melting furnace with a platinum or platinum-rhodium alloy coated on the surface, and even when bismuth glass is melted, it is a continuous melting furnace that can be mass-produced stably for a long period of time due to its deterioration (erosion and cracking). It was not enough.

  Therefore, the present invention eliminates the problems in the above conventional sealing composition, can be sealed at a temperature below the pre-baking without crystallization even if pre-baked above the sealing temperature, and platinum or An object of the present invention is to provide a low melting point glass of bismuth-based glass which can be melted stably with a material such as platinum-rhodium for a long period of time, a sealing composition using this glass, and a sealing paste.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that a composition containing a low-melting-point glass powder containing a glass composition shown below and a refractory ceramic filler solves the above-mentioned problems. Based on this finding, the present invention has been completed.

That is, the invention corresponding to claim 1 of the present invention contains substantially no lead and is expressed in mass%, Bi ₂ O ₃ 70 to 90%, ZnO 1 to 20%, B ₂ O ₃ 2 to 12 _{%, Al 2 O 3 0.1~5%} , CeO 2 0.1~5%, 0~5% CuO, Fe 2 O 3 0.01 ~0.2%, CuO + Fe 2 O 3 0.05~5 %, containing, and _{Li 2 O, Na 2 O,} K 2 the total amount of the alkali metal oxides such as O, and less than 0.1%, a molar ratio _{(CuO + Fe 2 O 3)} / Bi 2 O 3 = 0.01 to 0.036.

The invention corresponding to claim 2 is the low melting point glass of the invention corresponding to claim 1, wherein Al ₂ O ₃ / Bi ₂ O ₃ = 0.01-0. 1 is satisfied.

  The invention corresponding to claim 3 enables sealing at a temperature equal to or lower than this pre-baking without crystallizing even if pre-baking.

  The invention corresponding to claim 4 is a low melting point glass powder of 60 to 99% by volume of the invention corresponding to any one of claims 1 to 3, zircon, cordierite, aluminum titanate, alumina, mullite, silica, oxidation Seal containing 1 to 40% by volume of one or more refractory ceramic filler powders selected from the group consisting of tin-based ceramics, β-eucryptite, β-spodumene, zirconium phosphate-based ceramics and β-quartz solid solution It is a wearing composition.

  The invention corresponding to claim 5 is a sealing paste obtained by mixing a vehicle with the composition of claim 4.

  The reason for limitation of each component of the low melting glass which comprises the sealing composition of this invention is demonstrated below.

Bi ₂ O ₃ is an oxide that forms the network of the glass of the present invention, and is preferably contained in the range of 70 to 90%. When Bi ₂ O ₃ is less than 70%, the softening point of the low-melting glass becomes high and it cannot be used as a sealing composition capable of low-temperature sealing. On the other hand, if it exceeds 90%, it will not vitrify and the thermal expansion coefficient will be too high. The content of Bi ₂ O ₃ is more preferably 75 to 85% by weight in consideration of the load softening point, the thermal expansion coefficient, and the like. Here, the load softening point is the second variation of the heat balance curve obtained by raising the temperature of the glass-coated sample at a rate of 10 ° C./min using a differential thermal analyzer (DTA). The temperature indicated by the inflection point.

  ZnO is a component that lowers the thermal expansion coefficient and lowers the load softening point, and is preferably contained in the range of 1 to 20%. If ZnO is less than 1%, vitrification is difficult, and if it exceeds 20%, the stability during low-melting glass molding is poor and devitrification tends to occur, and glass may not be obtained. The ZnO content is more preferably 7 to 12% in consideration of the stability of the glass and the like.

Al ₂ O ₃ is a component that lowers the coefficient of thermal expansion and improves the stability of the low-melting glass during temporary firing, and is preferably contained in the range of 0.1 to 5%. When Al ₂ O ₃ is less than 0.1%, crystal nuclei or crystals are precipitated in the low-melting glass at the time of calcining at 500 ° C. or higher, and cannot be sealed at a temperature lower than that at the calcining. On the other hand, if it exceeds 5%, the viscosity of the glass increases, and Al ₂ O ₃ may remain as an unmelted material in the low-melting glass. Considering the thermal expansion coefficient, the stability of the glass, the meltability, etc., it is more preferably 0.5 to 2%.

Further, in order to expand the temperature range where low-melting glass can be sealed and to generate crystals even if pre-baked at a temperature higher than the expected sealing temperature, Al ₂ O ₃ / Bi ₂ O ₃ = 0.01- 0.1 is preferable. If it is less than 0.01, crystal nuclei or crystals are precipitated in the low-melting glass at the time of preliminary baking at 450 to 550 ° C., and it becomes impossible to seal at a lower temperature than in the preliminary baking. On the other hand, if it exceeds 0.1, the viscosity of the glass increases, and Al ₂ O ₃ does not melt completely. If Al ₂ O ₃ / Bi ₂ O ₃ is in the above range, a stable glass network can be formed without crystallizing the glass even if pre-baking at a temperature higher than the expected sealing temperature.

B ₂ O ₃ is a component that forms a glass skeleton and expands the range in which vitrification is possible, and is preferably contained in an amount of 2 to 12%. If B ₂ O ₃ is less than 2%, vitrification becomes difficult, and if it exceeds 12%, the softening point becomes too high, and even if a load is applied during sealing, sealing at low temperatures becomes difficult. The content of B ₂ O ₃ is more preferably 5 to 10% in consideration of a thermal expansion coefficient, glass stability, a load softening point, and the like.

Fe ₂ O ₃ is a component that has the effect of suppressing the crystallization at the time of sealing and expanding the temperature range capable of being sealed without increasing the viscosity, but when added excessively, the vitrification range becomes narrower. Therefore, its content is 0 . 01-0.2%.

  CuO is a component that lowers the viscosity of the glass and widens the temperature range that can be sealed, particularly on the low temperature side, and its content is 0 to 5%, preferably 0.1 to 3%. If CuO exceeds 5%, it is preferable to avoid excessive addition because the crystal deposition rate increases and the temperature range at which sealing can be performed on the high temperature side is narrowed, and phosphors may be deteriorated in electronic component applications.

Further, CuO and Fe ₂ O ₃ are essential components for improving the fluidity of the glass at 480 ° C. or less and stabilizing the glass at the time of temporary firing, and the total amount thereof is 0.05 to 5%. It is preferable. If it is less than 0.05%, the above effect cannot be obtained, and if it is more than 5%, the glass becomes unstable and the temperature range at which sealing can be performed on the high temperature side becomes narrow and crystallization tends to occur. A more preferable range is 0.1 to 2%.

Furthermore, in order to widen the sealable temperature range and achieve both the suppression of crystallization at the time of pre-baking at 450 to 550 ° C. and the sealable viscosity at a temperature equal to or lower than the pre-baking temperature, Fe to Bi ₂ O _{3 2} O ₃ and CuO relationship, satisfying the relation of the molar ratio _{(CuO + Fe 2 O 3)} / Bi 2 O 3 = 0.01~ 0.036. If it is less than 0.01, sufficient fluidity of the glass for sealing at a low temperature cannot be obtained even when a load is applied, and if it exceeds 0.036 , the temperature range that can be sealed becomes narrow, and the glass becomes higher than the expected sealing temperature. Is crystallized, and the low melting point glass of the present invention cannot be obtained. Cu and Fe are elements that easily undergo valence change, and when added within the above range, the viscosity of the glass decreases, and the valence change during heating suppresses the valence change of Bi and the glass does not crystallize. There is an effect.

CeO ₂ has the effect of suppressing Bi ₂ O ₃ in the glass composition from precipitating as metal bismuth during glass melting and stabilizing the fluidity of the glass, so its content is 0.1 to 5%. is there. If the content is less than 0.1%, the above effect cannot be obtained. If the content is 5% or more, the viscosity of the glass is increased and it becomes difficult to seal at 480 ° C. or less. More preferably, it is 0.1 to 3%.

  In addition, when bismuth glass is melted with a crucible made of platinum or an alloy containing platinum as a main component, if an alkali metal such as Li, Na, K, etc. is contained in the glass composition, the platinum deteriorates rapidly (erosion and It has been found that it becomes easy to crack. In order to suppress this, the total amount of alkali metals in the glass raw material is preferably less than 0.1%, more preferably 0.01% or less.

Further, within a range of 5% as a composition other than the _{above, SiO 2, V 2 O 5} , Ag 2 O, Co 2 O 3, MoO 3, Nb 2 O 3, Ta 2 O 5, Ga 2 O 3, Sb ₂ O ₃ , CaO, SrO, BaO, WO ₃ , P ₂ O ₅ , SnOx (x = 1 or 2), Cs ₂ O and the like can be contained.

However, it is preferred that SiO ₂ is B ₂ O ₃ and phase separation to the main component B ₂ O ₃ and Bi ₂ O ₃ crystals occurs easily, also be 1% or less because an effect to increase the glass viscosity . Also, alkaline earth metal oxides such as CaO, BaO and SrO are not as much as alkali metal oxides, but have the effect of degrading platinum and platinum-based alloys, so the total should be 1% or less. Is desirable. Addition of highly toxic components such as Tl ₂ O and CdO should be avoided.

The glass having the above composition is an amorphous glass having a low glass transition point of 400 ° C. or less and showing good fluidity. In addition, the thermal expansion coefficient at 30 to 300 ° C. is 90 × 10 ⁻⁷ / ° C. or more and 110 × 10 ⁻⁷ / ° C. or less, and high expansion material suitable for this is sealed without blending a refractory ceramic filler. Is possible.

  On the other hand, when sealing various packages and display devices made of materials that do not conform to the thermal expansion coefficient, it is necessary to use a mixture of refractory ceramic fillers to correct the difference in thermal expansion coefficient from the material to be sealed. Is possible. A fire-resistant ceramic filler can also be used when mechanical strength is insufficient.

  When mixing the refractory ceramic filler, the mixing ratio is preferably 60 to 99% by volume of the low-melting glass powder and 1 to 40% by volume of the refractory ceramic filler. The reason for limiting the ratio of the two in this way is that when the refractory ceramic filler is less than 5% by volume, the effect is not achieved, and when it exceeds 55% by volume, the fluidity is deteriorated.

  As refractory ceramic filler, zircon, cordierite, aluminum titanate, alumina, mullite, silica, tin oxide ceramic, β-eucryptite, β-spodumene, zirconium phosphate ceramic and β-quartz solid solution alone, Or they are preferably used in combination. Moreover, it is also possible to use black pigments, such as a Fe-Co-Cr complex oxide type, as a heat-resistant pigment.

  The vehicle used in the present invention is, for example, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, oxyethyl cellulose, benzyl cellulose, propyl cellulose, nitrocellulose, etc. dissolved in a solvent such as terpineol, butyl carbitol acetate, ethyl carbitol acetate, etc. And acrylic resins such as methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-hydroxyethyl methacrylate, for example, methyl ethyl ketone, terpineol, butyl carbitol acetate, ethyl carbitol acetate, etc. And those dissolved in these solvents.

  The viscosity of the glass paste for sealing may be adjusted to the viscosity suitable for the apparatus applied to the substrate, and can be adjusted by the ratio of the resin and the solvent and the ratio of the vehicle and the sealing composition.

  Known additives can be added to the glass paste for sealing, such as an antifoaming agent and a dispersing agent.

  For the production of the sealing glass paste, a known method such as a rotary mixer equipped with a stirring blade, a roll mill, a ball mill or the like can be used.

  Since the bismuth-based glass composition of the present invention does not contain a lead component, there is no fear of causing environmental problems. Moreover, it is possible to perform sealing without crystallizing even if pre-baked at 450 to 550 ° C. with a wide sealing temperature range, and simultaneous baking with a plurality of members carried out in the mass production process of PDP is possible. Become.

  Further, since the low melting point glass of the present invention does not contain an alkali metal component, even when melted with a member such as platinum or platinum-rhodium, almost no deterioration is observed, and stable operation can be performed in mass production.

The low melting point glass of the present invention does not substantially contain a lead component, Bi ₂ O ₃ 70 to 90%, ZnO 1 to 20%, B ₂ O ₃ 2 to 12%, Al ₂ O ₃ 0.1 to 5 %, CeO ₂ 0.1 to 5%, CuO 0 to 5%, Fe ₂ O ₃ 0.01 to 0.2%, and Al ₂ O ₃ / Bi ₂ O ₃ = 0.01 in molar ratio And satisfying the relationship of (CuO + Fe ₂ O ₃ ) / Bi ₂ O ₃ = 0.01 to 0.036 . Furthermore, the total amount of alkali metal oxides such as Li ₂ O, Na ₂ O, and K ₂ O is less than 0.1%.

  Then, the raw materials were mixed so as to be in the composition range described above to obtain a batch raw material, and this batch raw material was put in a platinum crucible and put in a furnace adjusted to 1000 to 1200 ° C. and melted for 30 to 90 minutes. The melted glass was formed into a sheet shape with a water-cooled roller, pulverized with a ball mill, and then passed through a 150-mesh sieve to obtain a low-melting glass.

  60 to 99% by volume of this low-melting glass, zircon, cordierite, aluminum titanate, alumina, mullite, silica, tin oxide ceramic, β-eucryptite, β-spodumene, zirconium phosphate ceramic and β-quartz A sealing composition was prepared by mixing 1 to 40% by volume of a powder of one or more refractory ceramic fillers selected from solid solutions. Then, the sealing composition is made into a paste with an organic vehicle or the like that decomposes below the sealing temperature so that it can be easily applied to an object to be sealed. Moreover, you may use the composition for sealing previously shape | molded in the shape of a to-be-adhered part.

  Examples of the present invention and comparative examples will be described in detail below with reference to Table 1.

(Example 1) As shown in Table 1, Bi ₂ O ₃ 80.6%, B ₂ O ₃ 7.2%, ZnO 11.2%, CeO ₂ 0.4%, Al ₂ O ₃ 0.2 %, Fe ₂ O ₃ 0.1%, CuO 0.3% are prepared as batch raw materials. This batch raw material was put into a platinum crucible, put into a melting furnace adjusted to 1100 ° C., and melted for 50 minutes. The molten glass was formed into a sheet shape with a water-cooled roller, and the glass having passed through a 150-mesh sieve was used as the low melting glass.

The molar ratio of Al ₂ O ₃ / Bi ₂ O ₃ in this low-melting glass is from 0.46 / 40.92 to 0.011, and the molar ratio of (Fe ₂ O ₃ + CuO) / Bi ₂ O ₃ is ( 0.15 + 0.89) /40.92 to 0.025.

  A cordingite 26 volume% and zirconium phosphate 2 volume% were added to 72 volume% of this low melting glass as a refractory ceramic filler, and it was set as the sealing composition. The glass transition point, load softening point, and softening point of this sealing composition were determined by a differential thermal analyzer (DTA). The glass transition point was 356 ° C, the load softening point was 380 ° C, and the softening point was 416 ° C. .

Moreover, the flow button diameter of this sealing composition was 19 mm, the sealing temperature after calcination temperature 550 ° C. was 460 ° C., and the thermal expansion coefficient was 72 × 10 ⁻⁷ / ° C. These measuring methods are shown below.

Flow button diameter: This indicates the fluidity of the composition at the time of sealing, and a sample powder (6.0 g) of the sealing composition is pressed into a cylindrical shape having a diameter of 12.7 mm with a load of 50 to 100 kg / cm ^2. It is the diameter which the composition for sealing flowed when it hold | maintained for 10 minutes at 480 degreeC after shaping | molding. The flow button diameter is desirably 17 mm or more and 28 mm or less. If the thickness is less than 17 mm, the glass composition is not sufficiently softened and does not adhere to the object to be sealed. If it is larger than 28 mm, the glass will flow too much and bubbles will be generated on the sealing surface, or the bonding surface will be deformed.

  Coefficient of thermal expansion: A sealing composition is filled in an alumina container, baked at 500 ° C. for 10 minutes, cooled, and then polished into a cylindrical shape having a length of 15 mm and a diameter of 5 mm. The amount of elongation was measured with a temperature increase rate of 10 ° C./min using a Rigaku thermomechanical analyzer 8310), and an average coefficient of thermal expansion of 30 to 300 ° C. was calculated.

  The glass paste was prepared by mixing the vehicle and the sealing composition as shown below.

  Vehicle: Ethyl cellulose (average molecular weight 75000) 2% and ethyl cellulose (average molecular weight 55000) 2% as a resin, terpinol 30% and butyl carbitol acetate 66% as a solvent were heated to 60 ° C. and stirred for 2 hours.

  Paste: A vehicle was added to the sealing composition at a mass ratio of 82:18 and mixed with a roll mill to obtain a sealing paste. Obtained. When the viscosity of the paste was measured with a B-type viscometer (HDBVII + manufactured by Brookfield), it was 65 Pa · S.

The sealing temperature was measured as follows. First, a sample substrate is prepared by applying the paste obtained above on a glass substrate (Asahi Glass Co., Ltd .: PD-200) with a thickness of 400 to 500 μm and a width of 3 mm. After pre-baking this sample substrate in an electric furnace set to a pre-baking temperature, another glass substrate is put on this sample substrate and a load of 500 g / cm ² is applied to the coating area of the sealing composition. The temperature at which the glass substrates can be bonded to each other after baking is shown.

  The platinum erosion property was confirmed by observing with a microscope the portion of the platinum crucible that was in contact with the platinum crucible after the raw material was charged into the platinum crucible and melted 10 times.

From the above results, the sealing composition of Example 1 was able to seal the glass substrate at 460 ° C. after the pre-baking without crystals being deposited in the glass even when pre-baking at 550 ° C. . Further, since no alkali metal components (Li ₂ O, Na ₂ O, and K ₂ O) were contained in the glass, platinum erosion was not observed.

(Examples 2 to 6)
Examples 2 to 6 are examples in which sealing compositions were prepared by the same method as in Example 1.

  As shown in Table 1, glass was melted in the same manner as in Example 1 except that the raw materials were mixed into batch raw materials, formed into a sheet with a water-cooled roller, and passed through a sieve with 150 mesh openings Was a low melting glass.

The low melting point glass has an Al ₂ O ₃ / Bi ₂ O ₃ molar ratio of 0.022 to 0.076, and a (CuO + Fe ₂ O ₃ ) / Bi ₂ O ₃ molar ratio of 0.011 to 0. 0.036. Even when the sealing composition in which the low-melting glass and the refractory ceramic filler were mixed was fired at a pre-baking temperature of 480 to 540 ° C., no precipitation of crystals was observed in all the glasses. Moreover, since the load softening point of low melting glass is 356-379 degreeC, it can be made to flow fully at 480 degrees C or less also as a sealing composition which mixes a refractory ceramic filler. Actually, as shown in Table 1, when the flow button diameter of the sealing composition was measured, it was 20 to 26 mm.

  In this sealing composition, Examples 2 and 3 were the same as Example 1, Examples 4 to 6 were sealing compositions, 2.5% nitrocellulose as resin, 4% terpineol as solvent, butyl carbitol. A vehicle prepared by stirring 2 hours while heating 90.5% of acetate and 3% of isoamyl acetate at 80 ° C. was added at a mass ratio of 80:20 and mixed with a roll mill to obtain a sealing paste. Obtained. When the viscosity of the paste was measured with a B-type viscometer, it was 64 to 69 Pa · S.

  Moreover, when the sealing temperature was evaluated using this paste, it was possible to bond the substrates in the range of 450 to 480 ° C.

When the thermal expansion coefficient of this sealing composition was measured using TMA, it was 70 to 76 × 10 ⁻⁷ / ° C., which was very close to the thermal expansion coefficient of the glass used for PDP and was distorted after sealing. There is nothing.

In this example, when the alkali metal oxides (Li ₂ O, Na ₂ O and K ₂ O) in the composition were not contained or 0.05%, no deterioration was observed in the platinum crucible. However, in Example 5, when a platinum crucible was observed after the tenth melting, slight erosion was observed at the bottom.

(Comparative Example 1)
Comparative Example 1 is an example that does not contain any of Al ₂ O ₃ and Fe ₂ O ₃ + CuO, which are requirements to be provided in the present invention. The obtained sealing composition crystallized at 500 ° C. and could not be sealed.

(Comparative Example 2)
Comparative Example 2 is an example in which Al ₂ O ₃ which is a requirement to be provided in the present invention is 0.1% or less. The obtained sealing composition crystallized at 500 ° C. and could not be sealed.

(Comparative Example 3)
Comparative Example 3 is an example in which Al ₂ O ₃ which is a requirement to be provided in the present invention is 0.1% or more but does not contain Fe ₂ O ₃ + CuO. The obtained sealing composition crystallized at 500 ° C. and could not be sealed.

(Comparative Example 4)
Comparative Example 4 is an example in which the Al ₂ O ₃ molar ratio, which is a requirement to be provided in the present invention, is Al ₂ O ₃ / Bi ₂ O ₃ > 0.1. The resulting sealing composition did not crystallize even at 550 ° C., but the viscosity of the low-melting glass was increased and the flow button at 480 ° C. was less than 17 mm, so that the fluidity was poor and could not be sealed.

(Comparative Examples 5 and 6)
In Comparative Example 5, Li ₂ O, and in Comparative Example 6, Na ₂ O and an alkali metal are each 0.1%. All of the obtained sealing compositions were not crystallized by calcination at 520 ° C. and could be sealed at 460 ° C., but in Comparative Example 5 the sixth glass melting and in Comparative Example 6 the eighth crucible. Cracks occurred at the bottom, and melting of the glass could not be continued.

  It goes without saying that the sealing composition of the present invention can be sealed without crystallization even if pre-baked at a sealing temperature or lower. Moreover, since there exists what crystallizes at the temperature exceeding 550 degreeC, it can be used as a lead-free crystallized glass of the member which can be sealed at high temperature exceeding 550 degreeC.

Claims (5)

Substantially free of lead,
In mass% display,
Bi ₂ O ₃ 70-90%,
ZnO 1-20%,
B ₂ O ₃ 2~12%,
Al ₂ O ₃ 0.1-5%,
CeO ₂ 0.1-5%,
CuO 0-5%,
Fe ₂ O ₃ 0.01 to 0.2%,
CuO + Fe ₂ O ₃ 0.05-5%,
And the total amount of alkali metal oxides such as Li ₂ O, Na ₂ O, K ₂ O is less than 0.1% ,
(CuO + Fe ₂ O ₃ ) / Bi ₂ O ₃ = 0.01 to 0.036 in molar ratio
A low-melting glass characterized in that Al ₂ O ₃ / Bi ₂ O ₃ = 0.01-0. 2. The low-melting glass according to claim 1, wherein the relationship 1 is satisfied.   The low-melting glass according to claim 1 or 2, which can be sealed at a temperature equal to or lower than the pre-baking without crystallizing even if pre-baking.   60 to 99% by volume of the low-melting glass powder according to any one of claims 1 to 3, zircon, cordierite, aluminum titanate, alumina, mullite, silica, tin oxide ceramic, β-eucryptite, β A sealing composition comprising 1 to 40% by volume of powder of at least one refractory ceramic filler selected from the group consisting of spodomen, zirconium phosphate ceramics and β-quartz solid solution.   A sealing paste obtained by mixing a vehicle with the sealing composition according to claim 4.