JP2006143480A - Bi2O3-B2O3-BASED GLASS COMPOSITION AND Bi2O3-B2O3-BASED SEALING MATERIAL - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based glass composition which is substantially free from PbO and can be fired at a temperature of ≤480°C and a Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based sealing material. <P>SOLUTION: The Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based glass composition contains, by mol, 35-60% Bi<SB>2</SB>O<SB>3</SB>, 10-35% B<SB>2</SB>O<SB>3</SB>, and 0.1-5% WO<SB>3</SB>as glass composition. The Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based sealing material is obtained by mixing the Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based glass composition containing, by mol, 35-60% Bi<SB>2</SB>O<SB>3</SB>, 10-35% B<SB>2</SB>O<SB>3</SB>, and 0.1-5% WO<SB>3</SB>as glass composition and a fire-resistant filler powder. The mixing volume ratio of the Bi<SB>2</SB>O<SB>3</SB>-B<SB>2</SB>O<SB>3</SB>-based glass composition to the fire-resistant filler powder is 40/60 to 90/10. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a Bi ₂ O ₃ —B ₂ O ₃ glass composition and a Bi ₂ O ₃ —B ₂ O ₃ sealing material suitable for adhesion, sealing, coating, etc. of electronic components.

  Conventionally, glass has been used as an adhesive material and sealing material for electronic components, and as a coating material for protecting and insulating electrodes and resistors formed on electronic components.

  These glasses are required to have various properties such as chemical durability, mechanical strength, fluidity, and electrical insulation depending on the application, but can be fired at low temperatures as a property common to all applications. Can be mentioned. Therefore, in any application, low-melting glass (for example, see Patent Document 1) containing a large amount of PbO that has an extremely large effect of lowering the melting point (softening point) of glass has been widely used.

  Recently, however, environmental problems have been pointed out with respect to low-melting glass containing PbO, and it is desired to replace it with a low-melting glass containing no PbO.

Therefore, various low melting glass has been developed as an alternative to low melting glass containing PbO. Among them, Bi ₂ O ₃ —B ₂ O ₃ -based low-melting glass (see, for example, Patent Document 2) has equivalent characteristics as compared with low-melting glass containing PbO in chemical durability and mechanical strength. Therefore, it is expected as an alternative candidate for glass containing PbO.
Japanese Unexamined Patent Publication No. Sho 63-315536 JP 2000-128574 A

Patent Document 2 exemplifies a bismuth-based low-melting glass composition that can be used for applications such as adhesion, sealing, and coating of electronic components. However, this Bi ₂ O ₃ —B ₂ O ₃ -based glass composition has a higher softening point than the glass containing PbO (the softening point of the glass containing PbO is about 480 ° C.) and has poor fluidity. Therefore, the usage is limited.

In order to lower the softening point, it is necessary to increase the content of Bi ₂ O ₃ as a main component. However, if the content of Bi ₂ O ₃ is increased, the glass itself tends to be crystallized, and Bi _2. The effect of increasing the content of O ₃ is difficult to obtain.

An object of the present invention is to provide a Bi ₂ O ₃ —B ₂ O ₃ glass composition and a Bi ₂ O ₃ —B ₂ O ₃ system that are substantially free of PbO and can be fired at a temperature of 480 ° C. or lower. It is to provide a sealing material.

The present inventor added the Bi ₂ O ₃ -B ₂ O ₃ -based glass composition with 0.1 to 5 mol% of WO ₃ to reduce the content of Bi ₂ O ₃ , which is a component that lowers the softening point. Even if it is increased, it has been found that the precipitation of crystals in the glass is suppressed and the firing temperature can be lowered, and is proposed as the present invention.

Bi ₂ O ₃ -B ₂ O ₃ based glass composition of the present invention has a glass composition, in _{mol%, Bi 2 O 3 35~60%,} B 2 O 3 10~35%, WO 3 0.1 It is characterized by containing ~ 5%.

Further, the Bi ₂ O ₃ —B ₂ O ₃ sealing material of the present invention has a glass composition in terms of mol%, Bi ₂ O ₃ 35-60%, B ₂ O ₃ 10-35%, WO ₃ 0 A sealing material in which a Bi ₂ O ₃ —B ₂ O ₃ glass composition containing 1 to 5% and a refractory filler powder are mixed, and the mixing ratio is expressed by volume%, Bi ₂ O ₃ − The B ₂ O ₃ glass composition is 40 to 90%, and the refractory filler powder is 60 to 10%.

In the Bi ₂ O ₃ —B ₂ O ₃ glass composition of the present invention, the content of Bi ₂ O ₃ , which is a component that makes the glass have a low melting point, is added by adding 0.1 to 5 mol% of WO _3. Even if it increases, it can suppress that a crystal | crystallization precipitates in glass. Therefore, it is excellent in fluidity and can be baked at a temperature of 480 ° C. or lower despite substantially not containing PbO.

The reason why the composition of the Bi ₂ O ₃ —B ₂ O ₃ glass composition of the present invention is limited as described above is as follows.

Bi ₂ O ₃ is a main component for lowering the softening point of the glass, and its content is 35 to 60%, preferably 40 to 55%, more preferably 42 to 52%. When the content of Bi ₂ O ₃ is less than 35%, the glass transition point tends to be too high and it tends to be difficult to fire at a temperature of 480 ° C. or less, and when it exceeds 60%, the glass becomes unstable and devitrification occurs. It tends to be easy to do.

B ₂ O ₃ is essential as a glass forming component, and its content is 10 to 35%, preferably 15 to 30%, and more preferably 18 to 28%. When the content of B ₂ O ₃ is less than 10%, the glass tends to become unstable and easily devitrified, and the fluidity necessary for operations such as adhesion, sealing, and coating cannot be obtained. There is. On the other hand, if it exceeds 35%, the viscosity of the glass tends to be high, and firing may be difficult at a temperature of 480 ° C. or lower.

WO ₃ is a component for preventing the fluidity from being lost due to crystallization when glass is reheated and fired, and is an essential component. Its content is 0.1 to 5%, preferably 0.1 to 1.5%. In order to lower the softening point, it is necessary to increase the content of Bi ₂ O ₃ which is a main component. However, if the content of Bi ₂ O ₃ is increased, the glass itself tends to be crystallized during firing. There is a tendency to inhibit fluidity. In particular, the effect becomes remarkable when it is 40% or more in terms of mol%. As the cause, and Bi ₂ O ₃ (Bisumaito) is a crystalline product which formed in the bismuth alone during firing, Bi ₂ O ₃ and composed of B ₂ O ₃ Metropolitan _{2Bi 2 O 3 · B 2 O} 3 or 12Bi ₂ O _This is thought to be due to the precipitation of ₃ · B ₂ O ₃ crystal. If a large amount of this crystal is precipitated, the fluidity is hindered. However, WO ₃ preferentially bonds with Bi ₂ O ₃ before these crystals are precipitated, and these crystals are precipitated. There is a function to suppress. However, addition of 5% or more is not preferable because it tends to deteriorate the stability of the glass.

Bi ₂ O ₃ -B ₂ O ₃ based glass composition of the present invention may contain the following components in addition to components described above.

  BaO, SrO, MgO and CaO have an effect of suppressing devitrification when the glass is melted, and the total content thereof is 1 to 15%, preferably 3 to 10%. If the total amount of these components is less than 1%, it is difficult to obtain the above effect, and if it exceeds 15%, the softening point tends to increase. The BaO content is preferably 0 to 10%, particularly preferably 2 to 8%. Moreover, about each content of SrO, MgO, and CaO, it is 0 to 5%, It is preferable that it is 0.5 to 3% especially.

  ZnO has an effect of suppressing devitrification when the glass is melted, and its content is 5 to 30%, preferably 10 to 20%. If the content is less than 5% or more than 30%, the glass tends to crystallize and the fluidity becomes poor.

  CuO is a component that suppresses devitrification when the glass is melted, and its content is 0 to 15%, preferably 2 to 10%. When CuO exceeds 15%, the precipitation rate of crystals tends to be extremely high and the fluidity tends to deteriorate.

Fe ₂ O ₃ is a component that suppresses devitrification when the glass melts, and its content is 0 to 5%, preferably 0.1 to 2%. If Fe ₂ O ₃ exceeds 5%, the glass tends to become unstable.

Moreover, it is preferable to add Al ₂ O ₃ , which is a component that suppresses devitrification when the glass is melted, because precipitation of crystals can be suppressed during firing. Its content is 0 to 5%, preferably 0.1 to 3%. Addition of 5% or more tends to increase the softening point of the glass and make it difficult to fire at a temperature of 480 ° C or lower.

SiO ₂ can be added up to 1% for the purpose of enhancing the weather resistance. If it exceeds 1%, the softening point of the glass tends to be high, and it tends to be difficult to fire at a temperature of 480 ° C. or lower.

  The oxides of Li, Na, K, and Cs are components that lower the softening point of the glass, but since they have an action of promoting devitrification of the glass, the total amount is preferably 2% or less.

P ₂ O ₅ is a component that suppresses devitrification, but if the amount added is more than 1%, it tends to cause phase separation, which is not preferable.

MoO ₃ , La ₂ O ₃ , Y ₂ O ₅ and CeO ₂ are components that stabilize the glass. However, if the total amount of these is more than 3%, the softening point of the glass increases, and the temperature is 480 ° C. or less. There is a tendency to be hard to fire at temperature.

PbO is preferably substantially not contained for environmental reasons. In addition, when PbO is contained in the low melting point glass, when used as an insulator, Pb ²⁺ may diffuse into the glass and the electrical insulation may be easily lowered.

The Bi ₂ O ₃ —B ₂ O ₃ glass composition having the above composition is an amorphous glass exhibiting good fluidity at a temperature of 480 ° C. or less, and has a coefficient of thermal expansion at 30 to 300 ° C. 110-120 × 10 ⁻⁷ / ° C. Therefore, adhesive material having substantially the same thermal expansion coefficient as Bi ₂ O ₃ -B ₂ O ₃ based glass compositions, sealing, when coating or the like, with Bi ₂ O ₃ -B ₂ O ₃ based glass composition Can be directly glued, sealed or coated.

On the other hand, Bi ₂ O ₃ —B ₂ O ₃ -based glass compositions and materials that do not match the thermal expansion coefficient, such as alumina (70 × 10 ⁻⁷ / ° C.), high strain point glass (85 × 10 ⁻⁷ / ° C.), When adhering, sealing or coating soda plate glass (90 × 10 ⁻⁷ / ° C.) or the like, a sealing material is prepared by mixing a Bi ₂ O ₃ —B ₂ O ₃ glass composition and a refractory filler powder. do it. It is important that the thermal expansion coefficient of the sealing material is designed to be lower by about 10 to 30 × 10 ⁻⁷ / ° C. than the object to be sealed. This is to prevent the sealing material from being broken by setting the strain applied to the sealing material after sealing to the tension (tensile) side. In addition to adjusting the thermal expansion coefficient, for example, a refractory filler powder can be added to improve mechanical strength.

When mixing the refractory filler powder, the mixing ratio is preferably 40 to 90% by volume of the Bi ₂ O ₃ —B ₂ O ₃ glass composition and 60 to 10% by volume of the refractory filler powder. The reason for defining the ratio of the two in this way is that when the refractory filler powder is less than 10% by volume, the above-described effect tends to be hardly obtained, and when it exceeds 60% by volume, the fluidity tends to be poor.

  As the refractory filler powder, powders of willemite, cordierite, β-eucryptite, zircon, tin oxide, mullite, quartz glass, alumina and the like can be used alone or in combination.

In particular, willemite and cordierite are preferable because they have a small coefficient of thermal expansion and hardly react with Bi ₂ O ₃ —B ₂ O ₃ glass.

  Further, it is preferable that the refractory filler powder is coated with alumina, zinc oxide, zircon, titania, zirconia or the like because the reaction between the glass and the refractory filler powder can be suppressed. In particular, alumina is preferable because it has a high melting point and hardly reacts with glass.

In addition, specific applications of the Bi ₂ O ₃ —B ₂ O ₃ glass sealing material of the present invention include (1) formation of a hermetic sealing material for plasma display panels (PDP), insulating layers and dielectric layers. Examples include materials, barrier rib forming materials, (2) sealing materials for fluorescent display tube (VFD) packages, insulating layer forming materials, and (3) sealing materials for magnetic head-cores or cores and sliders.

A sealing material in which a Bi ₂ O ₃ —B ₂ O ₃ glass composition and a refractory filler powder are mixed may be used as a sealing material as a powder, but the sealing material and the vehicle should be uniform. When kneaded and used as a paste, it is easy to handle.

  The vehicle mainly includes a solvent and a resin, and the resin is added for the purpose of adjusting the viscosity of the paste.

  Solvents include N, N′-dimethylformamide (DMF), α-terpineol, higher alcohol, γ-butyrolactone (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.

  As the resin, ethyl cellulose, polyethylene glycol derivatives, nitrocellulose, polymethylstyrene, polyethylene carbonate, methacrylic acid ester, and the like can be used.

  Hereinafter, the present invention will be described in detail based on examples.

  Tables 1 and 2 show the glass compositions of the examples (samples a to h) and the comparative examples (samples i and j).

  Each sample described in Tables 1 and 2 was prepared as follows.

  First, a glass batch in which raw materials such as various oxides and carbonates were prepared so as to have the glass composition shown in the table was prepared, and this was put in a platinum crucible and melted at 900 to 1000 ° C. for 2 hours.

  Next, a part of the molten glass was poured out into a stainless steel mold as a sample for measuring the coefficient of thermal expansion, and the other molten glass was formed into a thin piece with a water-cooled roller.

  Finally, the glass flakes were pulverized with a ball mill and passed through a sieve having an opening of 105 μm to obtain samples having an average particle diameter of about 10 μm.

  Using the above samples, the glass transition point, softening point, thermal expansion coefficient, firing temperature and gloss were evaluated.

  The glass transition point and softening point were determined by a differential thermal analyzer (DTA).

  The thermal expansion coefficient was determined by a push rod type thermal expansion measuring device.

  The firing temperature was evaluated as follows.

  First, a sample having a mass corresponding to the true specific gravity of each sample was put into a mold and pressed into a button shape having an outer diameter of 20 mm and a height of about 5 mm.

  Next, this button was placed on a plate glass, placed in an electric furnace, heated at a rate of 10 ° C./min, and held at various temperatures for 30 minutes. Of the buttons having an outer diameter of 21 to 22 mm, the firing temperature of the button fired at the lowest temperature was defined as the firing temperature of the sample.

  The gloss was evaluated by visual observation of the presence or absence of gloss on the sample surface after holding the button at the firing temperature for 30 minutes.

As apparent from Tables 1 and 2, samples a to h which are examples of the present invention have a glass transition point of 330 to 342 ° C., a softening point of 396 to 415 ° C., and a thermal expansion coefficient of 111 to 30 ° C. of 111. It was -117 * 10 < ^-7 > / degreeC, and the calcination temperature was 455 degrees C or less. Moreover, as for the firing state, the samples a to h all had gloss on the surface.

  On the other hand, samples i and j, which are comparative examples, had a baking temperature of 445 ° C. or lower, but had no gloss on the surface.

  Tables 3 and 4 show the sealing materials.

  Next, samples a to j and refractory filler powder were mixed at the ratios shown in Tables 3 and 4 to prepare sealing material powders (samples 1 to 10). Sample No. 1 to 8 are examples of the present invention, sample No. Reference numerals 9 and 10 respectively show comparative examples.

Samples 1 to 4 are sealing materials for VFD, and are materials for sealing two soda glass plates (coefficient of thermal expansion 90 × 10 ⁻⁷ / ° C.). Samples 5 to 10 are sealing materials for PDP, and are materials for sealing two high strain point glass plates (coefficient of thermal expansion 85 × 10 ⁻⁷ / ° C.).

  Moreover, willemite or cordierite was used for the refractory filler powder.

  Using the above samples, the thermal expansion coefficient, flow diameter, gloss and resealability were evaluated.

  The flow diameter is a temperature described in the table by pressing a powder having a weight corresponding to the true specific gravity of the sealing material powder into a button shape having an outer diameter of 20 mm using a mold and raising the temperature in air at a rate of 10 ° C./min. The diameter of the button when held for 10 minutes was measured and evaluated. In addition, it means that fluidity | liquidity is excellent in a flow diameter being 21 mm or more.

  Resealability was evaluated as follows.

  First, each sample and acrylic resin-containing α-terpineol were uniformly kneaded to form a paste, and then linear (80 × 100 × 3 mm) at the end of a substrate (100 × 100 × 3 mm) made of the same material as the sealed object of each sample. × 3 × 3 mm) and dried at 120 ° C. for 15 minutes.

  Next, the substrate was held at a temperature 10 ° C. higher than the firing temperature described in the table for the time described in the table, and then left in the room to cool the substrate.

  Subsequently, a glass plate having a thickness of 150 μm was placed in the middle of the substrate, and the substrates with the same dimensions were covered from above. Then, both substrates were fixed with clips, and fired again under the conditions described in the table.

  Evaluation was made as “◯” when the distance between the substrates was 150 μm after reflowing by firing, and “X” when the distance between the substrates was larger than 150 μm without sufficiently softening and flowing again. In addition, what was "(circle)" by this evaluation is considered that the devitrification did not arise in the heat processing at the time of binder removal.

As is apparent from Tables 3 and 4, Samples 1 to 8 had a thermal expansion coefficient of 71.1 to 76.5 × 10 ⁻⁷ / ° C. at 30 to 300 ° C. Moreover, the flow diameter of 21.1-22.5mm was shown on the baking conditions shown in the table | surface, and it had favorable fluidity | liquidity. Moreover, there was gloss and it was excellent in resealability.

  On the other hand, Samples 9 and 10 had no gloss and poor resealability.

  The reason why the resealability was not good in Samples 9 and 10 is considered to be that crystals were already deposited at the first firing. For this reason, it is considered that the crystal grew during the second firing and hindered the softening flow of the glass. In fact, when the surface state after the first firing was observed with an optical microscope, the precipitation of crystals could be confirmed.

The Bi ₂ O ₃ —B ₂ O ₃ glass composition of the present invention can be used for bonding, sealing, coating, etc. of electronic parts, specifically, PDP, field emission display (FED), surface electric field display (SED), VFD. It is suitable for sealing display tubes such as cathode ray tubes (CRT), PDP insulating dielectric layers, PDP barrier ribs, and magnetic head-core or core and slider sealing materials.

Claims (5)

Bi ₂ O ₃ -B ₂ characterized by containing Bi ₂ O ₃ 35-60%, B ₂ O ₃ 10-35%, WO ₃ 0.1-5% in terms of mol% as a glass composition. O ₃ glass composition. The Bi ₂ O ₃ -B according to claim 1, characterized by containing BaO + SrO + MgO + CaO 1 to 15%, ZnO 5 to 30%, CuO 0 to 15%, Fe ₂ O ₃ 0 to 5% in terms of mol%. ₂ O ₃ -based glass composition. _3. The Bi ₂ O ₃ —B ₂ O ₃ -based glass composition according to claim 1, wherein the glass composition does not substantially contain PbO. A sealing material obtained by mixing the powder and the refractory filler powder consisting of Bi ₂ O ₃ -B ₂ O ₃ based glass composition according to any one of claims 1 to 3, the mixing ratio by volume percentage Bi ₂ O ₃ —B ₂ O ₃ -based sealing, characterized in that the powder composed of Bi ₂ O ₃ —B ₂ O ₃ -based glass composition is 40 to 90% and the refractory filler powder is 60 to 10%. Landing material. The refractory filler powder is one or more filler powders selected from the group consisting of willemite, cordierite, β-eucryptite, zircon, tin oxide, mullite, quartz glass and alumina. The Bi ₂ O ₃ —B ₂ O ₃ sealing material according to claim 4.