JP6876537B2 - Stainless steel vacuum double container sealed lead-free glass composition - Google Patents

Description

The present invention relates to a sealing glass composition used for sealing at a low temperature, and more specifically, vacuum-sealing a stainless steel vacuum double container such as a thermos bottle, a portable heat insulating bottle, or a lunch jar at a low temperature. It relates to a sealed glass composition that can be worn and can hold a vacuum well.

The stainless steel vacuum double container is manufactured by performing a so-called degassing process in which the gas between the inner and outer containers is evacuated from the exhaust hole while heating the stainless steel double container in a vacuum furnace, and then further high temperature treatment. Then, the glass installed in the exhaust hole is allowed to flow, and the exhaust hole is closed, that is, a so-called sealing process is performed.
It is necessary to use a vacuum furnace for vacuum sealing. However, heat transfer in a vacuum furnace is only radiation, and in general, the temperature variation in the furnace tends to be large.
Further, it is necessary to hold the gas at a temperature of 300 to 320 ° C. for about 90 minutes as a degassing treatment before the sealing treatment. However, at this time, crystal nuclei are generated in the glass, and crystal precipitation tends to be promoted around the nuclei during the sealing treatment, and if crystal precipitation is promoted, the flow property deteriorates. The tendency to promote crystal precipitation becomes more remarkable as the degassing temperature is higher and the degassing time is longer. Therefore, the degree of crystal precipitation and the flowability vary depending on the variation in the temperature during degassing in the furnace.
The temperature and time during the sealing process also affect the degree of crystal precipitation and flowability. The temperature variation during the sealing process also greatly affects the sealing performance. Therefore, in order to suppress the variation in sealing performance, it is necessary to make it difficult for the glass to precipitate crystals and to reduce the melting value.
Conventionally, for vacuum sealing of a stainless steel vacuum double container using, for example, SUS304, lead glass that can be sealed at a low temperature has been used in order to prevent the stainless steel from being sharpened.
However, since lead glass contains a lead component as a main component, it has an adverse effect on the human body, the environment, and other points. Therefore, a glass containing no lead component is desired.
From such a background, in recent years, an attempt has been made to apply bismuth-based glass as an alternative to lead glass.

Japanese Unexamined Patent Publication No. 2000-128574 Japanese Unexamined Patent Publication No. 2006-321665 Japanese Unexamined Patent Publication No. 2008-24558 Japanese Unexamined Patent Publication No. 10-29834 JP-A-2015-44728

Patent Document 1 discloses a bismuth-based glass composition that can be fired at a temperature of 500 ° C. or lower for sealing purposes.
However, the glass composition disclosed in Patent Document 1 may be a non-crystalline glass or a crystalline glass depending on the selected composition, so that the glass composition lacks stability and causes a problem in the flowability of the glass. obtain.
Patent Document 2 discloses a bismuth-based lead-free glass composition in which a crystallization peak does not occur up to 500 ° C. Further, Patent Document 3 discloses a bismuth-based lead-free glass composition for sealing, which is suitable for vacuum-sealing a metal vacuum double container.
However, since the glass compositions disclosed in Patent Documents 2 and 3 do not contain _{TeO 2} , there is a problem that crystallization should be improved when the amount of _{Bi 2} O _{3 is increased to reduce the melting.}
Patent Document 4 _{discloses TeO 2-} WO _3- ZnO-based glass.
However, the glass of Patent Document 4 does not contain alkali metal and bismuth oxide, and there is a problem that the melting property should be improved.
Patent Document 5, is also disclosed TeO ₂ based glass.
However, the glass of Patent Document 5 _{does not contain WO 3} , and there is a problem that crystallization and low melting should be improved.

Therefore, the present invention solves the above-mentioned problems of the prior art, less crystal precipitation during firing such as degassing and vacuum sealing, and vacuum sealing of a stainless steel vacuum double container is good at a low temperature of 550 ° C. or lower. An object of the present invention is to provide a lead-free glass composition for wearing a vacuum double container made of stainless steel, which can be carried out with good yield and has excellent adhesiveness.

As a result of various studies and experiments in view of the problems of the prior art, the present inventor has made it difficult for crystals to precipitate at a low sealing treatment temperature of 550 ° C. or lower in tellurium-based glass, and to reliably seal the glass. We have found an excellent composition range and have completed the present invention.
The lead-free glass composition for wearing a stainless steel vacuum double container of the present invention evacuates between the inner and outer containers made of stainless steel through an exhaust hole, and vacuum seals the exhaust hole for the purpose of maintaining the vacuum between the inner and outer containers. Can be used for.

That is, the lead-free glass composition made of stainless steel of the present invention, which is sealed in a vacuum double container, is expressed in mass%, TeO ₂ : 40 to 60%, Bi ₂ O ₃ : 4 to 25%, WO ₃ : 4 to 25%. , ZnO: 2~25%, MgO, CaO, SrO, 0~20% in total of at least one or more of BaO, contain, and _PbO, the first feature that it does not contain V 2 _{O 5} It is said.
Further, in addition to the above first feature, the lead-free glass composition made of stainless steel of the present invention, which is sealed in a vacuum double container, has TeO ₂ : 45 to 60% and Bi ₂ O ₃ : 4 to 20% in terms of mass%. _{, WO 3: 4~20%, ZnO} : 2~20%, MgO, CaO, SrO, 0~10% in total of at least one or more of BaO, contain, and _PbO, the V 2 _{O 5} The second feature is that it does not contain.
Further, in addition to the above-mentioned second feature, the lead-free glass composition made of stainless steel of the present invention, which is sealed in a vacuum double container, has TeO ₂ : 48 to 55% and Bi ₂ O ₃ : 10 to 18% in terms of mass%. _{, WO 3: 8~18%, ZnO} : 2~15%, MgO, CaO, SrO, 2~5% in total of at least one or more of BaO, contain, and _PbO, the V 2 _{O 5} The third feature is that it does not contain.
Further, in addition to any of the above-mentioned first to third features, the stainless steel vacuum double container-sealed lead-free glass composition of the present invention has Li ₂ O, Na ₂ O, and K ₂ O in terms of mass%. The fourth feature is that at least one of the above is contained in a total of 7% or less.
Further, in addition to any of the above-mentioned first to fourth features, the stainless steel vacuum double container-sealed lead-free glass composition of the present invention has a mass% display of among _{B 2} O ₃ and Al ₂ O _3. The fifth feature is that at least one of the above is contained in a total of 10% or less.
Further, in addition to the above-mentioned first to fifth features, the stainless steel vacuum double container-sealed lead-free glass composition of the present invention contains at least one of CuO and CoO in terms of mass%. The sixth feature is that it contains 10% or less in total.

According to the stainless steel vacuum double container sealed lead-free glass composition according to claim 1, since the type and content of the glass component are within a predetermined range, crystals are less likely to precipitate during firing and the flowability is excellent. It is possible to actually provide a lead-free glass composition for wearing a stainless steel vacuum double container, which can be reliably sealed at a low temperature of 550 ° C. or lower, and is suitable for maintaining good heat retention.
Further, according to the stainless steel vacuum double container sealed lead-free glass composition according to claim 2, in addition to the action and effect according to the configuration of claim 1, by further limiting the content, the content is further limited. It is possible to provide a lead-free glass composition made of stainless steel, which is hard to precipitate crystals, and which is sealed in a vacuum double container.
Further, according to the stainless steel vacuum double container sealed lead-free glass composition according to claim 3, in addition to the action and effect according to the configuration of claim 2, the content is further limited to a range. It is possible to provide a lead-free glass composition for wearing a vacuum double container made of stainless steel, which is more resistant to crystal precipitation.

Further, according to the stainless steel vacuum double container sealed lead-free glass composition according to claim 4, in addition to the action and effect according to any of the configurations of claims 1 to 3, Li ₂ O is displayed in mass%. By containing at least one of Na ₂ O and K ₂ O in a total of 7% or less, it is difficult for crystals to precipitate at a lower temperature during firing, and the flowability is excellent, and it is easy at a low temperature of 550 ° C or lower. A stainless steel vacuum double container sealed lead-free glass composition that can be reliably sealed can actually be provided.
Further, according to the stainless steel vacuum double container sealed lead-free glass composition according to claim 5, in addition to the action and effect according to any of the configurations of claims 1 to 4, B ₂ O is displayed in mass%. _3. By containing at least one of Al ₂ O ₃ in total of 10% or less, it is difficult for crystals to precipitate at a low temperature during firing, excellent in flowability, and easily and reliably at a low temperature of 550 ° C or less. A stainless steel vacuum double container sealed lead-free glass composition that can be sealed can actually be provided.
Further, according to the stainless steel vacuum double container sealed lead-free glass composition according to claim 6, in addition to the action and effect according to any of the configurations of claims 1 to 5, CuO and CoO are displayed in mass%. By containing at least one of these in a total of 10% or less, it is even more difficult for crystals to precipitate at low temperatures during firing, and it has excellent flowability, and it can be easily and securely sealed at low temperatures of 550 ° C or lower. A stainless steel vacuum double container sealed lead-free glass composition can be provided.

The lead-free glass composition for wearing a stainless steel vacuum double container according to the embodiment of the present invention is suitable as a lead-free glass composition capable of vacuum-sealing a stainless steel vacuum double container by low-temperature firing and maintaining a good vacuum. Is.
Hereinafter, the reasons for limiting the content of each component of the lead-free glass composition for wearing a stainless steel vacuum double container according to the present embodiment will be described. In addition, all the following are expressed in mass%.

TeO ₂ is an oxide forming the glass of the present invention, and is contained in the range of 40 to 60%.
If TeO ₂ is less than 40%, the glass may not be obtained, and even if it is obtained, the moldability of the glass may be poor.
If TeO ₂ exceeds 60%, glass can be obtained, but the sealing may become unstable, which is not preferable.
The content of TeO ₂ is preferably 45 to 60%, more preferably 48 to 55%, and most preferably 50 to 52% in consideration of the moldability of the glass, the softening temperature, and the like. ..

Bi ₂ O ₃ is an essential component for stabilizing the glass state and reducing melting, and is contained in the range of 4 to 25%.
When Bi ₂ O ₃ is less than 4%, the softening point of the glass becomes high and the flowability deteriorates.
If Bi ₂ O ₃ exceeds 25%, the glass becomes unstable, crystals tend to precipitate during firing, the flowability deteriorates, and poor sealing occurs.
The content of Bi ₂ O ₃ is preferably 4 to 20%, more preferably 10 to 18%, and further preferably 14 to 16% in consideration of the moldability of the glass, the softening point, and the like. Most preferred.

WO ₃ is a component that prevents crystallization and is contained in the range of 4 to 25%.
If WO ₃ is less than 4%, the _{effect of adding WO 3} is insufficient and crystals are likely to precipitate.
When WO ₃ exceeds 25%, the softening point becomes high and the flowability deteriorates.
The content of WO ₃ is preferably 4 to 20%, more preferably 8 to 18%, and most preferably 10 to 15% in consideration of the moldability of the glass, the softening point, and the like. ..

ZnO is a component that lowers the melting of glass and improves the moldability of glass, and is contained in the range of 2 to 25%.
If ZnO is less than 2%, crystals are likely to precipitate.
If ZnO exceeds 25%, the glass becomes unstable and crystals tend to precipitate during firing.
The ZnO content is preferably 2 to 20%, more preferably 2 to 15%, and most preferably 5 to 15% in consideration of the moldability of the glass and the like.

MgO, CaO, SrO, and BaO are components that have the effect of reducing melting, stabilizing the glass, and suppressing crystal precipitation. Therefore, at least one or more of MgO, CaO, SrO, and BaO can be contained in a total of 0 to 20%.
Of course, it does not have to be contained, but when it is contained, it can be contained up to 20%, preferably 10%.
When MgO, CaO, SrO, and BaO exceed 20% in total, glass cannot be obtained, or even if glass is obtained, crystals are likely to precipitate.
In order to obtain a good effect of stabilizing the glass, it is more preferable to contain at least one of MgO, CaO, SrO and BaO in a total of 2 to 5%.

Li ₂ O, Na ₂ O, and K ₂ O are components that reduce the melting of glass. It does not have to be contained, but when it is contained _{, at least one of Li 2} O, Na ₂ O, and K ₂ O can be contained in a total of 7% or less.
When Li ₂ O, Na ₂ O, and K ₂ O are contained in an amount of more than 7% in total, glass cannot be obtained, or even if it is obtained, crystals are likely to precipitate.
In order to lower the sealing temperature, _{it is preferable to contain at least one of Li 2} O, Na ₂ O and K ₂ O in a total of 2 to 5%.

B ₂ O ₃ and Al ₂ O ₃ are components that stabilize glass. It does not have to be contained, but when it is contained, at least one kind or more can be contained in a total of 10% or less.
When B ₂ O ₃ and Al ₂ O ₃ are contained in excess of 10% in total, glass can be obtained, but the softening point of the glass becomes high and the glass does not flow at the target temperature.
In order to make the glass more stable, it is preferable to contain at least one of _{B 2} O ₃ and Al ₂ O _{3 in a total of 2 to 6%.}

CuO and CoO are components that lower the melting of glass and improve the adhesion to stainless steel. It does not have to be contained, but when it is contained, at least one kind or more can be contained in a total of 10% or less.
When CuO and CoO are contained in an amount of more than 10% in total, glass cannot be obtained, or even if it is obtained, crystals are likely to precipitate.
From the viewpoint of improving the adhesion to stainless steel, it is preferable to contain at least one of CuO and CoO in a total of 3 to 9%.

_{In addition to the above components, Fe 2} O ₃ , SiO ₂ , TiO ₂ and ZrO ₂ are added in total from 0.01 to for the purpose of improving stability during glass production, suppressing crystallization, and adjusting the coefficient of thermal expansion. 5%, preferably 0.01-1% can be added.

It does not contain lead oxide (PbO) and vanadium oxide (V ₂ O _5).
The expression "does not contain" here is the meaning of the raw material in the present specification as an active ingredient vanadium oxide and lead oxide _{(PbO) (V 2 O 5} ) is not used, each constituting a glass It does not exclude raw materials of ingredients and those mixed with trace amounts derived from others. In other words, it does not mean that even those contained as impurities do not fall within the scope of the present invention.

The stainless steel vacuum double container sealed lead-free glass composition of the present invention has a glass softening point Ts of 460 ° C. or lower and an average coefficient of thermal expansion α ^{of 120 to 180 × 10-7 / ° C. in the range of room temperature to 300 ° C.} It has and is suitable for vacuum sealing of stainless steel vacuum double containers.
The sealing glass of the present invention can be used, for example, in a sphere, a hemisphere, a marble shape, or a shape similar to the above.

Hereinafter, the present invention will be described in more detail with reference to examples. The present invention is not limited to these examples.

(Manufacturing of glass)
Raw materials include tellurium oxide, bismuth oxide, tungsten oxide, zinc oxide, magnesium hydroxide, calcium carbonate, strontium carbonate, barium carbonate, lithium carbonate, sodium carbonate, potassium carbonate, silicon oxide, boric acid, aluminum hydroxide, and copper oxide. , Cobalt oxide and the like were used.
As shown in Tables 1 to 6, the raw materials were prepared and mixed so as to have the glass compositions shown in Examples 1 to 40 and Comparative Examples 1 and 2.
Then, the mixture is placed in a platinum crucible, melted at a temperature of 850 to 950 ° C. for 1 hour, and then rapidly cooled by a twin roll method to obtain glass flakes, and the block is poured onto a preheated carbon plate to form a block. Made.
Then, the block was placed in an electric furnace set to a temperature about 50 ° C. higher than the expected glass transition point Tg, and slowly cooled.
The prepared glass flakes are remelted in a temperature range of 900 to 1000 ° C., the temperature is lowered until the viscosity becomes appropriate, and the glass flakes are dropped to form a hemispherical molded body having a diameter of about 5 mm, a height of about 2 mm, and a weight of about 180 mg. did.

(Evaluation)
For Examples 1 to 40 and Comparative Examples 1 to 2, the crystallization temperature of the glass powder and the coefficient of thermal expansion α of the glass block were measured by the following methods, and the flowability of the glass was determined.
The results are shown in Tables 1-6.

(1) Judgment of glass transition point Tg, softening point Ts, crystallization temperature, and crystallization Glass flakes were pulverized in a mortar to obtain glass powder. About 60 to 80 mg of the glass powder is filled in a platinum cell, and the temperature is raised from room temperature to 20 ° C./min using a DTA measuring device (Thermo Plus TG8120 manufactured by Rigaku Co., Ltd.) to obtain a glass transition point (° C.) and a softening point. It was measured whether (° C.) and the crystallization temperature (° C.) were detected.
Regarding crystallization, those having a crystallization temperature detected by the DTA measuring device of less than the upper limit of the firing temperature of 550 ° C. were evaluated as Δ, those of 550 ° C. or higher were evaluated as ◯, and those not detected were evaluated as ⊚.

(2) Coefficient of thermal expansion α
The obtained glass block was cut into a size of about 5 × 5 × 15 mm and polished to obtain a sample for measurement. ^{The coefficient of thermal expansion (× 10-7} / ° C.) based on two points of 50 ° C. and 300 ° C. was obtained from the thermal expansion curve obtained when the temperature was raised from room temperature to 10 ° C./min using a TMA measuring device. ..

(3) Flowability of glass The obtained hemispherical molded body was placed on a SUS plate, fired at a firing temperature of 480 ° C. and a holding time of 20 minutes, and the flowed diameter was measured to be 5.5 mm or less. Those of more than 5.5 mm to 7 mm were evaluated as Δ, those of more than 7 mm to 10 mm or less were evaluated as ◯, and those of more than 10 mm were evaluated as ⊚.

(Example 1)
As raw materials, tellurium oxide, bismuth oxide, tungsten oxide, and zinc oxide are used, prepared and mixed in a predetermined ratio, the mixture is placed in a platinum crucible, melted at a temperature of 950 ° C. for 1 hour, and then double-rolled. A block was prepared by quenching by the method to obtain glass flakes and pouring it onto a preheated carbon plate. After that, the block was placed in an electric furnace set to a temperature about 50 ° C. higher than the expected glass transition point, and slowly cooled.
The resulting glass flakes are crushed in a mortar to obtain glass powder, about 80 mg is filled in a platinum cell, and the temperature is raised from room temperature to 20 ° C./min using a DTA measuring device to obtain a glass transition point, a softening point, and the like. When the crystallization temperature was measured, it was 355 ° C, 412 ° C, and 558 ° C, respectively. Further, when the coefficient of thermal expansion α based on two points of 50 ° C. and 300 ° C. of the sample cut out from the glass block was determined, it was 146 × 10 ^-7 / ° C.
The prepared glass flakes were remelted at 1000 ° C., the temperature was lowered until the viscosity became appropriate, and the hemispherical molded product obtained by dropping was fired at 480 ° C. for 20 minutes, and the flow diameter was measured to be 8.3 mm. And the judgment was ○.
Examples 2 to 40 were also measured and evaluated in the same manner.

(Comparative Example 1)
Bismuth oxide, zinc oxide, calcium carbonate, barium carbonate, boric acid, aluminum hydroxide, copper oxide, and cobalt oxide are used as raw materials, and the mixture is prepared and mixed in a predetermined ratio, and the mixture is placed in a platinum crucible. After melting at a temperature of 950 ° C. for 1 hour, the glass flakes were obtained by quenching by a twin roll method and poured onto a preheated carbon plate to prepare a block. After that, the block was placed in an electric furnace set to a temperature about 50 ° C. higher than the expected glass transition point, and slowly cooled.
The resulting glass flakes are crushed in a mortar to obtain glass powder, about 80 mg is filled in a platinum cell, and the temperature is raised from room temperature to 20 ° C./min using a DTA measuring device to obtain a glass transition point, a softening point, and the like. When the crystallization temperature was measured, it was 353 ° C, 423 ° C, and 518 ° C, respectively.
Further, when the coefficient of thermal expansion α based on two points of 50 ° C. and 300 ° C. of the sample cut out from the glass block was determined, it was 110 × 10 ^-7 / ° C.
The prepared glass flakes were remelted at 1000 ° C., the temperature was lowered until the viscosity became appropriate, and the hemispherical molded product obtained by dropping was fired at 480 ° C. for 20 minutes, and the flow diameter was measured to be 5.5 mm. And the evaluation was x.

(Comparative Example 2)
As raw materials, bismuth oxide, zinc oxide, barium carbonate, sodium carbonate, boric acid, silicon oxide, and aluminum hydroxide are used, prepared and mixed in a predetermined ratio, and the mixture is placed in a platinum crucible at 950 ° C. After melting at a temperature for 1 hour, the glass flakes were obtained by quenching by a bi-roll method, and the glass flakes were poured onto a preheated carbon plate to prepare a block. After that, the block was placed in an electric furnace set to a temperature about 50 ° C. higher than the expected glass transition point, and slowly cooled.
The resulting glass flakes are crushed in a mortar to obtain glass powder, about 80 mg is filled in a platinum cell, and the temperature is raised from room temperature to 20 ° C./min using a DTA measuring device to set the glass transition point and softening point. When measured, it was 372 ° C. and 439 ° C., respectively. The crystallization temperature was not detected.
Further, when the coefficient of thermal expansion α based on two points of 50 ° C. and 300 ° C. of the sample cut out from the glass block was determined, it was 101 × 10 ^-7 / ° C.
The prepared glass flakes were remelted at 1000 ° C., the temperature was lowered until the viscosity became appropriate, and the hemispherical molded product obtained by dropping was fired at 480 ° C. for 20 minutes, and the flow diameter was measured to be 5.2 mm. And the evaluation was x.

The lead-free glass composition for stainless steel vacuum double container sealing of the present invention can be widely used in the stainless steel vacuum double container manufacturing industry.

Claims (6)

In mass% display,
TeO ₂ : 40-60%,
Bi ₂ O ₃ : 4-25%,
WO ₃ : 4-25%,
ZnO: 2 to 25%,
At least one of MgO, CaO, SrO, and BaO is 0 to 20% in total.
Contain, and PbO, V ₂ O ₅ stainless steel vacuum double container sealing lead-free glass composition characterized by containing no. In mass% display,
TeO ₂ : 45-60%,
Bi ₂ O ₃ : 4 to 20%,
WO ₃ : 4-20%,
ZnO: 2 to 20%,
At least one of MgO, CaO, SrO, and BaO is 0 to 10% in total.
Contain, and PbO, V ₂ O ₅ stainless steel vacuum double container sealing lead-free glass composition according to claim 1, characterized in that do not contain. In mass% display,
TeO ₂ : 48-55%,
Bi ₂ O ₃ : 10-18%,
WO ₃ : 8-18%,
ZnO: 2 to 15%,
At least one of MgO, CaO, SrO, and BaO at least 2-5% in total.
Contain, and PbO, V ₂ O ₅ stainless steel vacuum double container sealing lead-free glass composition according to claim 2, characterized in that do not contain. In mass% display,
The stainless steel vacuum double container seal according to any one of claims 1 to 3, wherein at least one of Li ₂ O, Na ₂ O, and K _{2 O is contained in a total of 7% or less.} Wearing lead-free glass composition. In mass% display,
The stainless steel vacuum double container sealed lead-free according to any one of claims 1 to 4, wherein at least one of B ₂ O ₃ and Al ₂ O _{3 is contained in a total of 10% or less.} Glass composition. In mass% display,
The lead-free glass composition for which a stainless steel vacuum double container is sealed according to any one of claims 1 to 5, wherein at least one of CuO and CoO is contained in a total of 10% or less.