WO2008013028A1

WO2008013028A1 - Lead-free glass composition for sealing metallic vacuum double container

Info

Publication number: WO2008013028A1
Application number: PCT/JP2007/063214
Authority: WO
Inventors: Junichi Nakamura; Yoshitaka Mayumi; Hideyuki Kuribayashi
Original assignee: Nihon Yamamura Glass Co., Ltd.
Priority date: 2006-07-24
Filing date: 2007-07-02
Publication date: 2008-01-31
Also published as: JP2008024558A

Abstract

It is intended to provide a lead-free glass composition for sealing a metallic vacuum double container, which is used for the vacuum sealing of the exhaust outlet of a metallic vacuum double container and contains in terms of an oxide thereof, Bi2O3: 75.0 to 83.0% by weight, B2O3: 5.0 to 10.0% by weight, ZnO: 5.0 to 10.0% by weight, BaO: 2.0 to 5.0% by weight, CuO: 0.5 to 2.0% by weight (however, not including 2.0% by weight), and CoO: 0.05 to 2.0% by weight and does not contain PbO and SiO2 as an active ingredient. The lead-free glass composition does not contain lead, deposits less crystal during firing such as during a degassing treatment or a vacuum sealing treatment, and is capable of performing sealing preferably and reliably in high yield at a low temperature not higher than 550°C.

Description

Lead-free glass composition for sealing metal vacuum double containers

Technical field

[0001] The present invention relates to a lead-free glass composition for sealing a metal vacuum double container. More specifically, the present invention relates to a lead-free glass composition capable of maintaining a good vacuum by vacuum-sealing a stainless steel vacuum double container such as a magic bottle, a portable heat retaining bottle, and a launcher at a low temperature. Background art

[0002] A vacuum double container made of metal, for example, stainless steel, needs to be evacuated (vacuum) by evacuating air in the gap between the inner and outer containers. For this reason, an exhaust hole is provided in the vacuum double container, air is exhausted from the exhaust hole at a predetermined exhaust processing temperature, and so-called degassing processing, and then the ambient temperature is further raised to the sealing temperature, A glass sealing composition placed in the vicinity of the exhaust hole is softened and closed to flow into the exhaust hole by its own weight, and the exhaust port is closed. I was jealous.

By the way, in the vacuum sealing of a stainless steel vacuum vessel using, for example, SUS304, lead glass that can be sealed at a low temperature has been conventionally used to prevent the sensitization phenomenon of stainless steel.

As this lead glass, for example, PbO—B 2 O − disclosed in JP-A-8-119670 is disclosed.

twenty three

There is a lead glass represented by ZnO—SiO 2 —A 1 O 2 —Bi 2 O 2 —V 2 O glass.

2 2 3 2 3 2 5

However, since lead glass contains lead as its main component, there is a problem with adverse effects on the human body, environment, and other points. For this reason, a glass containing no lead component has been desired. For this reason, SnO—PO disclosed in, for example, Japanese Patent Application Laid-Open No. 2005-350314 is used as a main component instead of lead glass. Phosphate glass is provided

twenty five

. Further, bismuth glass mainly composed of Bi 2 O disclosed in JP-A-2002-348152 and JP-A-2005-213103 is provided.

twenty three

Application is being attempted.

[0003] Patent Document 1: Japanese Patent Laid-Open No. 2005-350314 Patent Document 2: Japanese Patent Laid-Open No. 2002-348152

Patent Document 3: JP 2005-213103 PR

Disclosure of the invention

Problems to be solved by the invention

However, the specific gravity of the phosphate glass described in Patent Document 1 is small, so that the flowability (fluidity) is sufficient when firing without load as in the production of stainless steel vacuum double containers. However, there is a problem that the exhaust holes cannot be sealed well. In addition, since the bismuth glass described in Document 2 has a high melting point, the flowability of the glass is poor at a low temperature at which sensitization does not occur in austenitic stainless steel such as SUS304, for example, at a low temperature of 550 ° C or lower. There was a problem that the exhaust holes could not be sealed well.

Further, the bismuth glass described in the above-mentioned document 3 can be used for sealing even at a temperature of 520 ° C. or lower when firing is performed while applying weight. On the other hand, in the case of firing without load, since the low melting is not sufficient, there is a problem that the exhaust hole cannot be sealed well because the flowability at low temperature is poor and the stainless steel is not sensitized.

By the way, with bismuth glass, generally, when the glass is melted low, crystals are likely to precipitate. For this reason, crystals are liable to precipitate during firing, so that the flowability of the glass deteriorates and sealing cannot be performed well.

In the sealing process, a degassing process is performed as a pretreatment for the sealing process. In this degassing process, it is necessary to hold at a temperature of about 300 to 320 ° C. for about 90 minutes. However, if the treatment is performed under such conditions, crystal nuclei are generated in the glass of bismuth glass, which promotes crystal precipitation during the sealing treatment, and causes deterioration in flowability. This tendency becomes more prominent as the degassing temperature rises longer.

In addition, it is necessary to use a vacuum furnace in the vacuum sealing operation, but heat transfer in the vacuum furnace is only radiation, and generally there is a tendency for temperature variation in the furnace to increase. This variation in temperature appears as a variation in the degree of crystal precipitation in the sealing process using the glass treated therewith, and thus a variation in flow characteristics.

Of course, the temperature and time during the sealing process also affect the degree of crystal precipitation and flow properties. Thus, temperature variations during the sealing process also have a significant effect on the sealing performance.

According to the inventors of the present invention who analyzed the above problems, in order to suppress the fluctuation in sealing performance and ensure good and stable sealing in bismuth glass, the bismuth glass is made to have a low melting point and bismuth glass. The conclusion was reached that the suppression of crystal precipitation in glass is necessary.

[0005] Therefore, the present invention solves the above-mentioned problems with conventional glass compositions for sealing, does not contain lead, and crystal precipitation occurs during firing such as during degassing treatment and vacuum sealing treatment. It is an object of the present invention to provide a lead-free glass composition for sealing a metal vacuum double container that can be sealed well at a low temperature of 550 ° C. or less.

Means for solving the problem

[0006] As a result of intensive studies to solve the above problems, the present inventor has found that a BiO-based glass composition.

twenty three

As a result, it was found that sealing can be surely performed at a low sealing processing temperature of 550 ° C. or lower, and the present invention has been completed.

That is, the lead-free glass composition for sealing a metal vacuum double container of the present invention is a lead-free glass composition used for vacuum-sealing the exhaust port of a metal vacuum double container, in terms, Bi O: 75. 0~83 0 wt ^{_{0/0, BO:. 5.}} 0~: LO 0 weight ^{_{0/0, ZnO:. 5.}} 0~

2 3 2 3

10.0% by weight, BaO: 2.0 to 5.0% by weight, CuO: 0.5 to 2.0% by weight (excluding 2.0% by weight), CoO: 0.05 to 5.0 % By weight, containing PbO and SiO as active ingredients

2

The first characteristic is that it has no composition.

Here, PbO and SiO are not contained as active ingredients.

2

This means that it should not be included as a substantial component of the wearing glass composition. If PbO or SiO is contained as an impurity even if PbO or SiO is contained, this is also regarded as “active ingredient”.

2

Is not included. ”

Further, the lead-free glass composition for sealing a metal vacuum double container of the present invention, in addition to the above-mentioned first feature, is further converted to oxide in terms of Al O: 1.0% by weight or less, Fe O: 2. 0% by weight or less

2 3 2 3

NiO: The second feature is that the composition contains 2.0% by weight or less.

The invention's effect

[0007] According to the lead-free glass composition for sealing a metal vacuum double container according to claim 1, Do not contain lead harmful to the border or human body, and do not contain SiO.

2

Can be melted, and crystal precipitation during firing can be sufficiently suppressed. Therefore, it can be applied well to metal vacuum double containers, especially stainless steel vacuum double containers, and it is possible to perform vacuum sealing of exhaust holes at low temperature, reliably and with high yield.

[0008] Further, according to the lead-free glass composition for sealing a metal vacuum double container according to claim 2, the effect of the configuration according to claim 1 can be further improved by adding the component described above. Can be achieved reliably.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] The lead-free glass composition for sealing a metal vacuum double container of the present invention can be suitably used for vacuum-sealing a vacuum double container made of stainless steel at a low temperature, for example.

Further, the lead-free glass composition for sealing a metal vacuum double container of the present invention comprises bismuth oxide, boric acid, zinc oxide, barium carbonate, copper oxide, cobalt oxide, hydroxyaluminum hydroxide, iron oxide as raw materials. (Fe 2 O 3), acid nickel (NiO), etc.

twenty three

The raw materials are prepared, heated and melted at 1000 ° C. to 1100 ° C., held for 1 to 2 hours, and then molded into a rod-like, columnar, spherical, hemispherical, hajiki-shaped or the like.

[0010] The range of each component composition of the glass composition for sealing according to the present invention will be described.

Bi 2 O is a network forming oxide and an essential component for low melting.

twenty three

The content range is 75.0 to 83.0% by weight. If it is less than 75.0% by weight, the glass has a high softening point and poor flowability. On the other hand, if it exceeds 83.0% by weight, the glass becomes unstable, and crystals are likely to precipitate when the glass is baked, resulting in poor flowability and poor sealing.

Content range of Bi O are, preferably 77.0 to 82.0 wt ^_0/0. More preferably 78. 0

twenty three

-81.0% by weight.

[0011] B 2 O is a network-forming oxide essential for stabilizing the glass.

twenty three

The content range is 5.0 to L0% by weight. If the amount is less than 0% by weight, the glass becomes unstable, and crystals are likely to precipitate when the glass is fired, resulting in poor flowability. On the other hand, if it exceeds 10.0% by weight, the softness point of the glass becomes high and the flowability during firing is poor.

Content range of BO is a preferably 5.5 to 9.0 wt ^_0/0. More preferably 6.0 to 8. 0% by weight.

[0012] ZnO is an indispensable component because it has the effect of lowering the melting point of the glass and stabilizing the glass.

The content range is 5.0 to 10% by weight. 5. If it is less than 0% by weight, the soft spot of the glass will increase. In addition, crystal precipitation becomes violent and the flowability is remarkably deteriorated. On the other hand, if it exceeds 10.0 wt%, the glass becomes unstable and crystals are likely to precipitate.

The content range of ZnO is preferably 6.0 to 9.0% by weight. More preferably, it is 6.5 to 8.0% by weight.

[0013] BaO is an essential component and has the effect of reducing the melting and stabilizing of the glass and suppressing the crystallization during firing.

The content range is 2.0 to 5.0% by weight. 2. If it is less than 0% by weight, the softening point becomes high. In addition, crystals are likely to precipitate during glass firing. On the other hand, if it exceeds 5.0% by weight, the glass becomes unstable, crystals tend to precipitate during glass firing, and the flowability deteriorates.

Content range of BaO is a preferably 2.5 to 4.5 wt ^_0/0. More preferably, the content is 3.0 to 4.0% by weight.

[0014] CuO is an essential component, which lowers the melting temperature of the glass and stabilizes it, suppresses crystal precipitation during firing of the glass, and improves flowability. It also has the effect of improving adhesion with stainless steel.

The content range is 0.5 to 2.0% by weight (excluding 2.0% by weight). If it is less than 0.5% by weight, the above effect of CuO addition becomes insufficient, and crystals are likely to precipitate during glass firing. On the other hand, even if the CuO additive is 2. O% by weight or more, crystals tend to precipitate and the flowability deteriorates.

The CuO content is preferably 1.0 to 1.9% by weight. More preferably, it is 1.5 to 1.8% by weight.

[0015] CoO is an essential component. It stabilizes the glass, improves wettability with stainless steel, and has the effect of suppressing crystal precipitation during firing.

The content range is 0.05-2.0% by weight. If the amount is less than 0.05% by weight, the above effect due to the addition of CoO becomes insufficient, and crystals tend to precipitate during glass firing. Meanwhile, Co When O addition exceeds 2. O wt%, the soft point rises and the flowability during glass firing deteriorates.

Content range of CoO is preferably between 0.1 to 1.5 wt ^_0/0. More preferably, the content is 0.2 to 1.0% by weight.

[0016] Al O is an optional component that stabilizes the glass by adding force, and does not produce a result during glass firing.

twenty three

Effective in suppressing crystal precipitation.

The content of Al 2 O is 1.0% by weight or less. 1. If it exceeds 0% by weight, the soft spot increases.

twenty three

Flowability deteriorates during glass firing. In addition, undissolved material may remain when the glass is melted, and may be easily crystallized during firing.

The content of Al 2 O is preferably 0.05 to 0.5% by weight. More preferably 0.1 to 0.

twenty three

3% by weight.

[0017] Fe O is an optional component that stabilizes the glass by adding force,

twenty three

Effective in suppressing crystal precipitation. Furthermore, it has the effect of improving the adhesion to stainless steel.

The content of Fe 2 O is 2.0% by weight or less. 2. If it exceeds 0% by weight, the soft spot increases.

twenty three

When the glass is fired, the flowability is poor.

The content of Fe 2 O is preferably 1.0% by weight or less. More preferably 0. 05-0. 3

twenty three

Weight%.

[0018] NiO has the effect of stabilizing the glass and improving its adhesion to stainless steel by adding force, which is an optional component.

The NiO content should be 2.0% by weight or less. 2. If the content exceeds 0% by weight, the soft point rises and the flowability deteriorates when the glass is fired.

The content of NiO is preferably 1.0% by weight or less. More preferably, the content is 0.1 to 0.5% by weight.

[0019] Note that SiO is a network-forming component of glass and contributes to stability of the glass at the time of melting. Shi

2

The glass composition of the present invention is not included in the glass composition because it promotes the precipitation of crystals during firing and deteriorates the flowability of the glass.

[0020] In addition, VO has the effect of lowering the viscosity of the glass and lowering the surface tension. Occasionally, the precipitation of crystals is promoted and the flowability is deteriorated. Alkali metal oxides such as Li 0, Na 0, and KO are network modifiers.

2 2 2

If it is contained, the glass is melted low, but becomes unstable, and crystals are likely to precipitate during firing. Also, durability is deteriorated. Considering that stainless steel vacuum double containers such as thermos can be cleaned with an automatic dishwasher, etc.

2

Alkali metal oxides such as 0, Na 0 and K 2 O are preferably not included.

twenty two

[0021] The glass composition having the first and second features of the present invention described above has a glass transition point Tg of 360 ° C or lower, and is 100 to L 10 in the range of room temperature to 250 ° C. It has an average coefficient of thermal expansion O of X 10 ^_7 / K.

Such a glass composition having the first and second features of the present invention does not cause the sensitization phenomenon of stainless steel! / For firing at ヽ temperature! In addition, it has a sufficient flow property suitable for sealing, and can sufficiently suppress crystal precipitation. Therefore, it is suitable as a glass composition for sealing a stainless steel vacuum double container.

[0022] As described above, the production of the lead-free glass composition for sealing a metal vacuum double container of the present invention includes, as raw materials, bismuth oxide, boric acid, zinc oxide, barium carbonate, copper oxide, cobalt oxide. , Aluminum hydroxide, iron oxide (Fe 2 O), nickel oxide (NiO), etc.

twenty three

Each raw material is prepared so as to have a composition, and this prepared raw material is heated and melted at 1000 to 1100 ° C.

Here, in the preparation of the glass composition of the present invention, the blended raw material is once heated and melted and then cooled to form glass flakes. Further, the glass flakes are subjected to a process of remelting at 1050 to: L 100 ° C. It is preferable to employ a step of forming a molded body such as a rod, cylinder, sphere, hemisphere, or hafaki. The reason why the final raw material is manufactured through the remelting process after melting and cooling the compounded raw material into glass flakes as follows is as follows.

[0023] That is, the first-stage melt obtained by directly melting the raw material for preparation contains undissolved substances and crystals in the melt, and composition irregularities (the composition of the composition depending on the location in the melt). Even if stirring is introduced, it is not easy to eliminate the undissolved substances, the presence of crystals, and the compositional unevenness. Such undissolved materials, crystals, and melt power with uneven composition can be obtained when the glass is obtained during firing. Crystallization is easily promoted by using melts and crystals as nuclei, and the composition of each glass compact varies.

On the other hand, the above-mentioned problem can be solved by adding a step of first cooling the glass flakes and remelting them. The second-stage glass melt force, in which unmelted material, crystals, and compositional irregularities are reduced by remelting, suppresses crystal precipitation during firing, and reduces the variation in yarn content between glasses. Obtainable . As a result, the exhaust holes of the vacuum double container can be easily and reliably sealed at a low temperature.

Remelting temperature is 1050 ~: L100 ° C. When the temperature is lower than 1050 ° C, undissolved substances and crystals do not dissolve. When the temperature is higher than 1100 ° C, easily volatile components such as BiO are volatilized and the composition is reduced.

twenty three

Wake up.

Example

[0024] The present invention will be further described below with reference to examples. It should be noted that the present invention is not limited to these examples.

About Examples 1-5 and Comparative Examples 1-4 so that it may become a component composition shown in Table 1 and Table 2, a raw material was prepared and mixed, this was melted at 1000-: L100 degreeC, and then a rapid cooling roll was carried out. Used to obtain glass flakes. This glass flake is remelted at a temperature of 1050 ~: L100 ° C, and then the melt temperature is lowered until the viscosity becomes an appropriate viscosity, and droplet forming is performed. The diameter is about 4 mm, the thickness is about 2 mm, and the mass is about 200 mg of hemispherical glass was obtained.

Similarly, in order to obtain the component compositions shown in Tables 1 and 2, the raw materials were prepared and mixed for Examples 6 to 10 and Comparative Examples 5 to 7, and melted at a temperature of 1000 to 1100 ° C. The melt temperature was lowered until a suitable viscosity was obtained, and a hemispherical glass was obtained in the same manner as described above.

[0025] [Table 1] Implementation Implementation Implementation Implementation Implementation Implementation Implementation Implementation Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Example 9

Bi ₂ 0 ₃ 79.5 79.5 79.0 81.0 79.6 79.1 82.0 82.0 83.0

B ₂ 0 ₃ 6.8 6.9 6.8 6.5 6.9 6.9 5.8 6.5 5.3

ZnO 7.75 7.8 7.7 7.0 7.8 7.8 6.5 7.0 6.2 G BaO 3.5 3.3 3.6 3.1 3.5 3.5 3.5 2.5 2.2

CuO 1.8 1.8 1.8 1.65 1.75 1.1 1.8 1.6 1.3 pairs

CoO 0.4 0.3 0.4 0.5 0.1 1.1 0.4 0.4 2.0

A1 ₂ 0 ₃ 0.1 0.1 0.3 0.1 0.05 0.5

Sat Fe ₂ 0 ₃ 0.05 0.1 0.1 0.05

NiO 0.1 0.2 0.3 0.1 0.3

v ₂ o ₅

K ₂ 0

Glass transition point

344 347 350 341 348 352 340 339 342

Tg (° C)

Thermal expansion coefficient

108 109 108 109 108 107 107 109 107

(X10- ⁷ ZK)

Flowability ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ Crystallization ◎ ◎ ◎ ◎ ◎ ◎ 〇 △ Durability 〇〇〇〇〇〇〇 Comprehensive judgment ◎ ◎ ◎ ◎ 〇〇〇 Δ

2] Implementation Comparison Comparison Comparison Comparison Comparison Comparison Comparison Example 10 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7

Βι ₂ 0 ₃ 76.1 64.5 72.7 81.8 83.7 79.6 79.6 79.6

Β ₂ 0 ₃ 8.0 11.0 10.0 7.0 4.8 6.9 6.9 6.9

ΖηΟ 9.0 13.0 10.0 4.5 8.0 7.8 7.8 7.8 Ga BaO 3.9 5.3 3.9 5.2 1.3 3.5 3.3 3.1

CuO 1.9 2.5 1.9 2.2 1.5 1.8 1.8 pairs

CoO 1.0 2.5 1.5 1.5 0.4 0.4 0.3

A1 ₂ 0 ₃ 0.1 1.2

Sat Fe ₂ 0 ₃

NiO

Si0 ₂ 0.2 v ₂ o ₅ 0.3

K ₂ 0 0.5 Glass transition point

355 394 373 340 334 347 349 339

Tg (° C)

Thermal expansion coefficient

105 87 99 108 108 109 107 110

(X 10- ⁷ ZK)

Flowability Δ X X Δ △ X X △ Crystallization ◎ Δ ◎ X X X X X Durability ○ ○ ○ ○ ○ ○ ○ X Comprehensive judgment Δ X X X X X X X

The hemispherical glass samples of Examples 1 to 10 and Comparative Examples 1 to 7 were placed on a SUS304 stainless steel plate and held at 320 ° C. for 90 minutes as degassing conditions. Next, as a sealing treatment condition, it was kept at 520 ° C. for 20 minutes and baked.

The glass surface after firing was observed, and flowability, degree of crystallization, durability, and comprehensive judgment were made.

For flowability, d / h is 14 or more, where d is the glass diameter after firing and h is the thickness. ◎ (excellent), 10 (less than 14), ◯ (good), 6 or more, but less than 10, △ (possible), and less than 6, X (impossible).

Regarding crystallization, within the range of 2 mm X 2 mm on the glass surface after firing, ◎ if the number of precipitated crystals that can be confirmed with the naked eye is less than 10; Gloss was not confirmed, but △ was given when crystal precipitation was only on the surface, and X was given when crystal formation was observed up to the inside. When crystal precipitation is only on the surface, there is no problem with vacuum sealing.

In terms of durability, a boiling test using tap water was conducted for 1 hour.

[0028] The overall judgment was as follows.

If the flowability and crystallization are both ◎ and the durability is ◯, the overall judgment is ◎. If either flowability or crystallization is ◎, the other is 、, and the durability is 〇, the overall judgment is 〇.

If either flowability or crystallization is △ and durability is ◯, the overall judgment is △. If either flowability, crystallization or durability is X, the overall judgment is X. It was. Comprehensive judgment: ◎, ○, and △ are those that can be used without any trouble in vacuum sealing. Those with X will interfere with vacuum sealing.

[0029] Further, for measuring the transition point Tg of glass, a glass powder was measured using a DTA apparatus. The coefficient of thermal expansion α was measured using a TMA apparatus obtained by cutting a glass barta body into approximately 5 mm × 5 mm × 15 mm.

The results are shown in Tables 1 and 2.

[0030] As is apparent from the table, in Examples 1 to 4, the overall judgment was ◎. Moreover, in Examples 5-8, the comprehensive judgment was (circle). In Examples 9 and 10, the overall judgment was Δ. On the other hand, in Comparative Examples 1 to 7, the overall judgment was X.

[0031] As described above, the lead-free glass composition for sealing a metal vacuum double container of the present invention can be used favorably for vacuum sealing of a metal vacuum double container using a stainless steel. Helps keep the double container vacuum and keep the heat retention good.

Claims

The scope of the claims

[1] A lead-free glass composition used for vacuum-sealing the exhaust port of a metal vacuum double container, in terms of oxide,

Bi O:. 75. 0~83 0 weight ^_0/0

twenty three

BO: 5. 0~:. LO 0 weight ^_0/0

twenty three

ZnO: 5.0 to: L0.0% by weight

BaO: 2.0 to 5.0% by weight

CuO: 0.5 to 2.0% by weight (excluding 2.0% by weight)

CoO:. 0. 05~2 0 weight ^_0/0

And a composition that does not contain PbO and SiO as active ingredients

2

A lead-free glass composition for sealing a vacuum double container made of a genus.

[2] Further in terms of oxide

Al O: 1.0 wt% or less

twenty three

Fe 2 O: 2.0% by weight or less

twenty three

NiO: 2.0% by weight or less

The lead-free glass composition for sealing a vacuum double container made of metal according to claim 1, wherein the composition is a composition comprising