KR20020090921A - Metal-made vacuum double container and method of manufacturing the same, composition for sealing up - Google Patents

Abstract

PURPOSE: To provide a metallic vacuum double container having no problem against human and environment, having no problem in recycling stainless steel, or having excellent yield in sealing and which is coated with a fluororesin. CONSTITUTION: The purpose is attained by carrying out the sealing using a low melting point glass sealing material 43 having a softening temperature higher than fluorocarbon coating sintering temperature and degassing temperature at the time of evacuation, and not impeding reusing of inner and outer containers 1, 2 even in simultaneous melting together with the inner and outer containers 1, 2, for example, which does not contain lead or others contained in conventional low melting point glass sealing materials, and which does not contain ingredients having food hygienical problem.

Description

Metal vacuum double container and manufacturing method thereof, sealing composition {METAL-MADE VACUUM DOUBLE CONTAINER AND METHOD OF MANUFACTURING THE SAME, COMPOSITION FOR SEALING UP}

BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a metal vacuum double container, a method for manufacturing the same, and a sealing composition that can be used in the same. The present invention relates to a metal vacuum double container suitable for the present invention, a method for producing the same, and a composition for sealing.

The metal vacuum double container has a high thermal insulation between the inner and outer containers as a vacuum insulation space, and stainless steel products are the mainstream in terms of low thermal conductivity, corrosion resistance, and strength. In order to make the vacuum insulation space between the inner container and the outer container, vacuum exhaust through the exhaust hole is performed first, and then the exhaust hole is sealed by a sealing material and sealed while maintaining the vacuum exhaust state.

Vacuum evacuation is carried out in a heating atmosphere in a heating furnace in order to increase the evacuation efficiency, and the encapsulation treatment is performed by softening or melting the encapsulant in a vacuum exhaust state to close the exhaust pores, and then harden the encapsulant.

Here, the higher the temperature at the time of performing the vacuum exhaust, the better the exhaust efficiency. However, if the temperature is to soften or melt the sealing material, the sealing material cannot be arranged in advance with respect to the internal and external containers. However, it is difficult to arrange | position a sealing material later, maintaining the vacuum exhaust state. Here, the conventional vacuum exhaust temperature is set to be less than the softening point of the sealing material, and then the encapsulation treatment is carried out by raising the temperature to the temperature at which the sealing material softens or melts while maintaining the vacuum exhaust state.

Japanese Laid-Open Patent Publication No. 06-169850 uses a low-temperature molten glass having a softening temperature of 200 ° C to 600 ° C as a sealing material, and the exhaust temperature is 200 ° C to 600 ° C for a vacuum exhaust temperature of about 950 ° C. Discloses a technique to suppress.

In the above publication, a low temperature melting glass B ₂ O ₃ -PbO-based, B ₂ O _{3 -ZnO-based, PbO-B 2 O 3 -ZnO} -SiO 2 _{type, PbO-B 2 O 3 -Al} 2 O 3 - SiO ₂ system, and using an adhesive for glass, such as PbO-B ₂ O ₃ -SiO _{2 type, PbO-B 2 O 3 -BaO} -SiO 2 system.

As a result, low temperature exhaust and low temperature encapsulation are possible, and the vacuum heating furnace is not special and the cost is reduced. In addition, since the metal double container is not oxidized, the oxide removal work becomes unnecessary. The wettability with the double container of a sealing material improves, and a yield is improved. Since the double container is made of low temperature annealing, it is said that there is an advantage that the hardness is higher than that of high temperature annealing.

On the other hand, in the metal vacuum double container in which the fluorine coating is applied to at least one surface of the inner and outer containers, as shown in Fig. 4, the fluorine paint firing temperature may be as high as about 380 ° C and about 40 ° C. Corresponding to this, in a conventional vacuum double container made of fluorine coating, sealing is performed by using a metal sealing material such as Ni solder, and the sealing is prevented from being destroyed by the high temperature during subsequent fluorine paint firing.

However, when the metal sealing material is used, the encapsulation treatment temperature is about 1010 ° C., and thus, when the low melting point glass sealing material is used, advantages such as low temperature exhaust and low temperature encapsulation cannot be obtained.

In addition, even if the metal sealing material of the high temperature softening point area similar to the glass sealing material is adopted, since lead is a main component, it affects the human body, the environment, and the apparatus. In particular, there is a problem in the case of food-related heat containers. The conventional encapsulation processing unit seals to prevent intrusion of water and the like, and prevents lead from eluting by intrusion water, but takes time for work. In addition, in the vacuum heating furnace to be heated, the metal oxide component in the sealing material to be softened or melted is also likely to evaporate and escape, and is included in the exhaust to be evacuated, but it is difficult to completely separate it from the worker in the working environment. For this reason, it is necessary for the worker to take protective measures by a protective mask or protective clothing, and since the activities are restricted, it becomes difficult to work and the work efficiency is lowered. In addition, it is necessary to completely remove lead components and the like in the exhaust so as not to pollute the environment. In any case, it can be expensive and cause a rise in product costs. In addition, lead emanating from the vacuum furnace is naturally attached to and deposited on the inner surface of the furnace. It is difficult to remove the deposited lead in the state of so-called deposition plating, and because it is also a secondary source of lead, the device is relatively early in its life, and the operating cost (e.g., due to maintenance or replacement of the device) running costs) increases, affecting product costs.

In addition, even if the internal and external containers of the stainless steel product encapsulated with a lead-containing sealing material are dissolved and reused, if a large amount of lead remains in the molten stainless steel, it cannot be reused.

Moreover, in the conventional low melting glass sealing material, there is still a gap in the coefficient of thermal expansion of stainless steel, which further hinders the yield improvement in terms of adhesion and sealing properties.

The main object of the present invention is to be sealed by a low-melting glass sealing material that satisfies at least one of the conditions of no problem for people and the environment, no recycling of stainless steel, and excellent yield of encapsulation treatment, and furthermore, It is to provide a painted vacuum vacuum double container. In addition, it is a superior metal that can solve the conventional problem of adversely affecting the human body, the environment, and the device, and having low adhesion or sealing property to the stainless steel, which hinders dissolution reuse of internal and external containers. It is a manufacturing method of a vacuum double container, and providing the sealing glass composition used for these.

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a sectional view of an electric port bottom part of a metal vacuum double container obtained in an embodiment of the present invention.

2 is an overall cross-sectional view of the electric port of FIG.

Figure 3 is a graph showing the relationship between the temperature and the processing time when the vacuum vacuum and the metal vacuum double container of Figure 1 manufactured by the vacuum exhaust and encapsulation process compared with the conventional example.

Figure 4 is a graph showing the temperature change when the fluorine paint is applied to the encapsulated metal vacuum double container and calcined.

* Description of the symbols for the main parts of the drawings *

1: container 2: outer container

3: vacuum insulation space 41: exhaust hole

43: low melting point glass sealing material

In order to achieve the above object, the metal vacuum double container of the present invention becomes a vacuum insulation space between the inner container and the outer container of the stainless steel product by the vacuum exhaust treatment through the exhaust hole, at least one of the inner and outer containers In the case where the fluorine coating is added to the surface, the exhaust hole is sealed by a low melting glass sealing material having a softening point higher than the fluorine paint firing temperature and the degassing temperature at the time of vacuum exhaust. One feature is that it does not interfere with the reuse of internal and external containers by simultaneous dissolution with internal and external containers.

Moreover, although lead is a food hygiene problem with other heavy metals, the low melting glass sealing material which encloses the exhaust hole of this invention is also characterized by not containing the component which is problematic in food hygiene.

The low-melting-point glass sealing material that can cope with the fluorine coating, food hygiene, and dissolution of stainless steel is smaller than the thermal expansion coefficient of stainless steel, and the thermal expansion coefficient has a coefficient of thermal expansion of 25 × 10 ^-7 / K or less. Doing.

If the stainless steel is a martensitic stainless steel, there is an advantage that it is not sensitive to low temperature exhaust and low temperature encapsulation above the fluorine paint firing temperature.

Bismuth-based glass in which the low-melting-point glass sealant is substantially free of lead, in order to satisfy any of the above characteristics, 70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, and 5 to 29 wt% of B ₂ O ₃ . , ₁ to 15 wt% of SiO ₂ , 0 to 10 wt% of Al ₂ O _3, and 0 to 10 wt% of Cu 0. In this case, the sealing material for other materials such as metal or ceramic other than stainless steel or It is also effective as a sealing glass composition.

In addition, but not required to CuO as required above, 70~90wt% of Bi ₂ O _3, 0~2wt% of ZnO, 5~28wt% of B ₂ O _3, 1~15wt% of SiO _2, Al ₂ the O ₃ as including 0~10wt%, Cu0 0.5~6wt%, and when the CuO are required to slightly suppress the B ₂ O ₃ in 5~28wt% can be enhanced and adhesion to the metal in particular.

In order to manufacture the metal vacuum double container with the above characteristics, the material of each case is evacuated between the inner and outer containers of the stainless steel product at a temperature lower than the softening point of the low melting glass sealant through the exhaust hole. After degassing, the low-melting-point glass sealing material may be softened or melted at a temperature equal to or higher than the softening point in the vacuum exhaust state to seal the exhaust hole.

(Example)

Best Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the drawings to aid in understanding the present invention.

This embodiment is an example in the case of manufacturing the metal vacuum double container A which comprises the electric port B as shown in FIG. 2 with a stainless steel plate. However, as long as the inner container 1 and the outer container 2 are combined and the vacuum insulation space 3 is provided between both sides, any form and use may be sufficient. In addition, the metal vacuum double container itself may be a combination of the inner container 1 and the outer container 2, or may be formed integrally.

The electric port B of this embodiment accommodates the metal vacuum double container A in the outer case 21 made of synthetic resin to form a gas 23, and between the outer case 21 and the upper end of the metal vacuum double container A. The gas opening 25 is formed through the inlet portion 24 of the metal vacuum double container A of the base 23 by the shoulder member 22 made of synthetic resin, and the cover of the base 23 ( 26) is supported by the hinge pin 27 at the rear part so that opening and closing is possible. The heater 29 is brought into contact with a portion of the bottom 28 of the metal vacuum double container A so as to heat the contents. The discharge path 32 which discharges the contents liquid to the outside by connecting the electric pump 31 to the bottom part 28 of one layer is connected. The cover 26 is provided with a manual pump 33 for pressurizing the contents solution and extruding it through the discharge passage 32. The lid 26 is provided with a metal inner cover 34 covering the inlet portion 24 of the metal vacuum double container A and a vapor passage 35 through which the steam is drawn out. The operation panel 36 is provided on the upper surface of the protrusion 22a protruding in front of the shoulder member 22, and the discharge port 32a of the discharge path 32 opens downward on the lower surface of the protrusion 22a. .

The metal vacuum double container A performs the degassing operation of evacuating between the inner container 1 and the outer container 2 in the exhaust hole 41 shown in FIG. 1 while heating, and then exhaust gas 41 in this vacuum exhaust state. ) Is sealed. After the sealing treatment, the fluorine coating layer 37 shown in FIGS. 1 and 2 is provided on the inner circumferential surface of the inner container 1 of the metal vacuum double container A. As shown in FIG. The metal vacuum double container A may comprise an electric pot or a thermos bottle which is exposed to itself, and in this case, fluorine coating may also be performed on the outer circumferential surface of the outer container 2. The exhaust hole 41 is formed in the innermost part of the recessed part 40 in the outer container 2 as an example. The inner container 1 and the outer container 2 are evacuated with the concave portion 40 upward, during which the sealing material is stably positioned in the concave portion 40, and softens or melts after the evacuation. The sealing material naturally flows into the exhaust hole 41, and the sealing of the exhaust hole 41 is terminated when cooling solidifies. In the vacuum insulation space 3 formed in this manner, a getter 42 as a degassing agent is provided, and the gas generated in the vacuum insulation space 3 thereafter is absorbed by a predetermined time and absorbs a predetermined amount of gas. Maintain the degree of vacuum.

The fluorine coating carries out the baking process by conveying the inside of the heating furnace set about 385 degreeC to the conveyor after coating film formation. During the treatment, the temperature change shown in FIG. 4 described above is traced and maintained at a high temperature of about 380 ° C. for a predetermined time.

In order to perform the above encapsulation treatment, the enclosed metal vacuum double container A of this embodiment is not broken even in accordance with the fluorine paint firing temperature, and is softened or melted at a temperature sufficiently lower than that of a conventional metal encapsulating material to be low temperature exhaust and low temperature encapsulation. This low melting point glass sealing material 43 is used. In other words, between the inner container 1 and the outer container 2 of the stainless steel product is a vacuum insulation space 3 by vacuum exhaust treatment, and at least one surface of the inner container 1 and the outer container 2 is replaced with fluorine. In the metal vacuum double container to which the coating layer 37 is attached, the exhaust hole 41 is enclosed by the low melting glass sealing material 43 which has a softening point higher than the fluorine paint baking temperature and the degassing temperature at the time of vacuum exhaust. The low-melting-point glass sealing material 43 is a temperature range in which the sensitivity of the inner container 1 and the outer container 2 does not occur, and the work hardening remains, so that the plate thickness of the inner container 1 and the outer container 2 is suppressed small. Softening or melting in the range, the degassing temperature is set lower than that. When martensitic stainless steels, such as JIS SUS436, are used as stainless steel, work hardening can be left | maintained like general stainless steel, without sensitizing even at 60 degreeC.

The softening point of the low melting glass sealing material 43 needs to be about 380 degreeC or more and about 600 degreeC so that it may not be influenced by the fluorine paint baking temperature. It is preferable to set the degassing temperature to about 450 degreeC or more and less than 600 degreeC with respect to 600 degreeC which is the upper limit of the softening point of the low melting-point glass sealing material 43 on the degassing efficiency by vacuum exhaust. Therefore, the practical softening point range of the low-melting-point glass sealing material 43 becomes about 450 to 600 degreeC.

As a result, the vacuum double container A made of the metal of the present embodiment is evacuated and encapsulated in a lower temperature region than the metal sealing material suitable for the low melting point glass sealing material 43, and the thickness of the work hardened powder due to unannealing is reduced. In addition, the softening point of the low-melting-point glass sealing material 43 is higher than the degassing temperature, so that softening and melting during degassing operation do not cause deformation and loss, so that the sealing treatment is surely achieved, and the softening point is higher than the fluorine paint firing temperature. By being high, it is possible to provide a vacuum double container made of fluorine coated metal without breaking the encapsulation, thereby making it lighter than the conventional metal sealing material used for fluorine coating and at the same time reducing the product cost.

By the way, it is thought that the metal vacuum double container is reused when discarded for reasons of deformation, injury, fouling, discoloration, dysfunction, or out of fashion. It dissolves the material of the stainless steel of the discarded metal vacuum double container once, but if the glass sealant containing the conventional lead is used, if it remains in the dissolved stainless steel component, it may cause problems due to food hygiene, environment, and equipment. It becomes and becomes impossible to reuse.

However, in the present embodiment, the use of the low melting point glass sealing material 43 substantially free of lead does not prevent dissolution and reuse of the stainless steel material, thereby contributing to resource reduction and product cost reduction.

In addition, although lead is a food hygiene problem with other heavy metals, etc., the low melting glass sealing material 43 of this embodiment does not contain a food hygiene problem component such as lead. Thereby, there is no problem in that the metal vacuum double container A is used for food-related things, such as an electric pot, a portable thermos, a lunch box, a thermal cooking pan, and a mug. As a conventional low melting glass sealing material having food hygiene problems, the encapsulation position is limited to a part of the outer container 2, and when the encapsulation position comes into contact with cold or hot water, the lead component is eluted, There was a problem in that it took time to seal and prevent the impact. On the other hand, in the low melting glass sealing material 43 which does not contain substantial lead of this embodiment, these problems are solved, and it is possible to use safety and to reduce cost. At the same time, in the encapsulation process in a vacuum furnace, lead, which is harmful to people, the environment, and the device, is not emitted to the surroundings, so that countermeasures when lead is released are unnecessary, and the life of the device is also long. The metal vacuum double container A can be manufactured easily and inexpensively.

The low-melting-point glass sealing material 43 of this embodiment has a thermal expansion coefficient smaller than the thermal expansion coefficient of stainless steel, and the difference of thermal expansion coefficient becomes 25x10 <^-7> / K or less. The low-melting-point glass sealing material 43 is compressed in the exhaust hole due to shrinkage difference during cooling due to its thermal expansion coefficient being smaller than that of stainless steel, thereby increasing the adhesiveness of each other, and the difference due to the small difference between the thermal expansion coefficients of both. Since compression does not cause problems such as peeling, the sealing property is improved and the yield of the product in the sealing treatment is improved.

If the stainless steel is a martensitic stainless steel represented by SUS436, there is an advantage that it is not sensitive to low temperature exhaust and low temperature encapsulation at or above the fluorine paint firing temperature.

As the low melting point glass sealing material 43 which satisfies the above characteristics may be mentioned bismuth-based glass, more preferably a composition containing _{Bi 2 O 3, ZnO, B} 2 O 3, SiO 2, Al 2 O 3, CuO desirable.

Bi ₂ O ₃ is preferably contained in the range of 70 to 90 wt% as the network former of the glass. If it is less than 70 wt%, there exists a possibility that the softening point of glass may become high and it cannot become sealing by the heat processing at the temperature below about 600 degreeC. Moreover, when it exceeds 90 wt%, glass will easily devitrify (crystallize) and there exists a possibility that a glass transition point may fall too much. In consideration of the softening point of the glass, the meltability and the like, the content of Bi ₂ O ₃ is more preferably 75 to 86 wt%.

ZnO is a component that is highly effective for low melting of glass, but is highly volatile due to its high vapor pressure. Therefore, in order to prevent fluctuations in the composition, contamination of the heat treatment furnace, and the like, since there is evaporation, especially during heat treatment in vacuum, the weight ratio is preferably 2 wt% or less. In consideration of low melting of glass and the like, it is preferable to contain ZnO in an amount of 0.5 wt% or more.

B ₂ O _{3 is} also an essential component for low melting of glass due to the structure of glass. B ₂ O ₃ is preferably contained in the range of 5~29wt%. If B ₂ O ₃ is less than 5 wt%, the effect of low melting is small, and if it exceeds 29 wt%, the water resistance may deteriorate. In consideration of low melting of glass, water resistance, and the like, the content of B ₂ O ₃ is more preferably 6 to 21 wt%.

SiO _{2 is} also a glass structure, which is an essential component for stabilizing the glass. SiO ₂ is preferably contained in the range of 1~15wt%. The SiO ₂ is less than 1wt% there is a fear that the effect of stabilizing the glass become insufficient. On the contrary, if it exceeds 15 wt%, the softening point may be excessively increased, and the sealing and sealing may not be possible by heat treatment at a predetermined temperature. Moreover, when a base material is metals, such as stainless steel, a thermal expansion coefficient becomes too small than that of a base material, and there exists a possibility that a stress may arise and adhesive force may fall. In consideration of the stabilization of the glass, the softening point, the coefficient of thermal expansion, and the like, the content of SiO ₂ is more preferably ₂ to 10 wt%.

Al ₂ O ₃ is a component that prevents devitrification of the glass and stabilizes the glass. However, when the content of Al ₂ O ₃ exceeds 10 wt%, the softening point is excessively increased, making it difficult to seal and encapsulate it by heat treatment at a predetermined temperature. In consideration of the stabilization of the glass, the softening point, and the like, the content of Al ₂ O ₃ is more preferably 1 to 6 wt%.

Cu0 may be contained in an amount of 10 wt% or less for the purpose of increasing the adhesion of the glass to the stainless steel substrate when the substrate is a metal, particularly stainless steel. If CuO exceeds 10 wt%, the softening point may be too low. Considering the adhesiveness to a base material, a softening point, etc., it is preferable that content of CuO is 0.5-6 wt%.

In view of the above, in order for the bismuth-based low melting glass seal 43 to satisfy any of the above characteristics, 70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 29 wt% of B ₂ O ₃ , and SiO ₁ to 15 wt% ₂ , 0 to 10 wt% Al ₂ O ₃ and 0 to 10 wt% Cu0. In this case, as a sealing material for metals such as Al other than stainless steel or other materials such as ceramics It is effective also as a glass composition which consists of.

As described above, CuO does not have to be an essential component, but 70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 28 wt% of B ₂ O ₃ , ₁ to 15 wt% of SiO ₂ , and Al _2, the O ₃ as including 0~10wt%, the Cu0 0.5~6wt%, and when the CuO or the like to slightly suppress the B ₂ O ₃ in 5~28wt% are required, in particular to increase the adhesion to the metal .

70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 23 wt% of B ₂ O ₃ , ₁ to 10 wt% of SiO ₂ , 0 to 6 wt% of Al ₂ O ₃ , and 0.5 to Cu 0. When it contains-6 wt%, it becomes suitable for sealing and sealing to stainless steel.

70 to 86 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 21 wt% of B ₂ O ₃ , ₂ to 10 wt% of SiO ₂ , 0 to 6 wt% of Al ₂ O ₃ , and 0.5 to Cu 0. When it contains-6 wt%, it is suitable for stainless steel, especially martensitic stainless steel.

In order to apply the low-melting-point glass sealing material 43 in this embodiment to the sealing and encapsulation of a base material made of various materials, it is necessary to make the coefficients of thermal expansion close to each other. However, on the one hand, sealing and encapsulation are not broken according to the processing temperature required for the substrate, and the low melting glass sealant 43 is made of various elements such as materials on the substrate side and semiconductors mounted thereon according to the sealing and encapsulation temperature. It is also necessary to satisfy the softening point does not impair the function of. In general, raising the softening point increases the coefficient of thermal expansion.

In the case of using martensitic stainless steel or a material having the same thermal expansion coefficient, the thermal expansion coefficient of the bismuth-based low melting point glass is preferably 82 to 105 x 10 ^-7 / K, and the softening point is preferably 450 to 550 ° C. . Moreover, it is preferable that glass transition point is 370-450 degreeC.

Regarding the above compositions, Examples 1 to 6 and one comparative example are as shown in Table 1 below.

In addition, the measurement of a glass transition point, a glass softening point, and a thermal expansion coefficient, and evaluation of adhesiveness, an external appearance, and sealing property were performed as follows.

The glass transition point and the softening point are about 80 mg of each powder sample having a particle diameter of about 45 to 75 μm in a platinum microcell of a differential thermal analyzer (DTA), and the temperature is increased to 800 ° C. at a temperature rising rate of 20 K / min from room temperature. Was measured. The temperature of the shoulder part of the endothermic start part shown first was made into the glass transition point, and the temperature at which heat absorption is complete | finished through the minimum point was made into the softening point.

The coefficient of thermal expansion is measured using a thermomechanical analyzer (TMA), and the sample is processed with a glass rod with a diameter of about 5 mm and a length of 15 to 20 mm. Quartz glass is used as a standard sample and 10 K / min from room temperature. It was calculated | required as an average value of 30-350 degreeC from the TMA curve obtained by raising temperature at the temperature increase rate of.

Adhesion and appearance were evaluated by placing a glass rod shaped into a diameter of about 2 mm and a length of about 6.5 mm on the exhaust port of a double container of stainless steel, and heat-sealing at 600 ° C. for 15 minutes at a pressure of 1.33 Pa or less to make it encapsulated. . The adhesiveness evaluated whether glass flowed and adhered on the exhaust port, and the appearance was visually evaluated. The appearance is mainly judged by the presence or absence of devitrification or foam. Sealability was evaluated by the presence or the degree of vacuum leakage due to peeling or misalignment of the glass sealing material after firing the fluorine paint at 400 ° C and being sucked into the exhaust port. Either evaluation also made good (circle), (triangle | delta) a defect, and defect as X.

Here, it is as showing in Table 2 below about the glass transition point, the glass softening point, and the coefficient of thermal expansion with respect to the low melting-point glass sealing material which is the conventional lead glass.

In addition, when the thermal expansion coefficient of the JIS standard SUS304 used in the conventional stainless steel bottle and the SUS436 used in the present example is compared, it is as Table 3 below.

In order to manufacture the metal vacuum double container A which exhibits the above characteristics, as shown in FIG. 3 using the material of each said Example, the exhaust hole is made between the inner container 1 and the outer container 2 of a stainless steel product. After degassing by vacuum evacuation at a temperature lower than the softening point of the low melting point glass sealing material 43 through, for example, 450 ° C., the low melting point glass sealing material 43 is subjected to a temperature above the softening point, for example, 600 in this vacuum exhaust state. The exhaust hole 41 is sealed by softening or melting at 占 폚, and then fluorine paint is fired at about 380 占 폚 to form the fluorine coating layer 37.

Specifically, as shown in FIG. 1, the low-melting-point glass sealing material 43 is disposed in the recess 40 of the inner container 1 and the outer container 2 to prepare the preparation chamber, the first degassing chamber and the third degassing chamber. It takes 30 minutes to pass at a constant speed, and then passes through at a constant speed for about 15 minutes in the next soldering chamber and about 1 hour in a slow cooling chamber without a heater, and 40 in a cooling chamber by the last N ₂ gas. It takes about minutes to pass at constant speed. At this time, in a preparation room, it heats up from room temperature to 430 degreeC, and maintains at this temperature. In the following 1st degassing chamber, it raises early to 450 degreeC, and maintains it at that temperature. The said 450 degreeC is maintained in a 2nd degassing chamber and a 3rd degassing chamber. In the meantime, the 1st-3rd degassing chamber is set to predetermined vacuum degree, for example, the pressure of 1.33 Pa or less, and vacuums between the inner container 1 and the outer container 2 at the pressure of 1.33 Pa or less. In the soldering chamber, the low-melting-point glass sealing material 43 is softened or melted at a sealing temperature of about 600 ° C. in a vacuum exhaust state in which the same pressure state as the previous chamber is maintained. (3) is formed. After the sealing treatment, the temperature is lowered to the temperature at the time of vacuum exhaust by natural cooling in the slow cooling chamber without the heater, and then forced cooling to the normal temperature in the N ₂ gas chamber. 3, the temperature in () shows a series of processing temperatures in the case of the conventional low melting glass sealing material. In this way, the enclosed metal vacuum double container A is fluorine-coated and calcined while conveying the inside of the heating furnace maintained at about 385 ° C. at a constant speed by a conveyor to form a fluorine-coated layer 37. The firing time is about 30 minutes, and the metal vacuum double container (A) is maintained at about 380 ° C. for the latter 17 minutes.

According to the present invention, the softening point of the low melting point glass sealing material is lower than the degassing temperature, while reducing the thickness of the work hardened material due to the vacuum exhaust and encapsulation treatment at a lower temperature region than the metal sealing material suitable for the low melting point glass sealing material, and thus not being annealed. As it is high, it does not soften and melt during degassing operation and does not cause deformation or loss. Therefore, the encapsulation treatment is reliably achieved. Since it is higher than the fluorine paint firing temperature, the encapsulated metal vacuum double container can be provided without breaking the encapsulation. In addition, the weight of the product is reduced compared to the conventional method of using a metal sealing material for fluorine coating.

Claims (10)

In a vacuum vacuum container made of stainless steel, a vacuum insulated space is formed between the inner container and the outer container by a vacuum exhaust treatment through the exhaust hole, and the fluorine coating is added to at least one surface of the inner container and the outer container. Exhaust holes are sealed by a low melting glass sealant which has a softening point higher than the fluorine paint firing temperature and the degassing temperature during vacuum exhaust, and does not interfere with reuse of the inner and outer containers even when the inner and outer containers are dissolved simultaneously. Metal vacuum double container, characterized in that. In the metal vacuum double container between the inner and outer containers of stainless steel products, which is a vacuum insulation space through the vacuum exhaust treatment through the exhaust hole, and the fluorine coating is added to at least one surface of the inner and outer containers, A metal vacuum double container having a softening point higher than the fluorine paint firing temperature and the degassing temperature at the time of vacuum evacuation, and the exhaust hole being sealed by a low-melting-point glass sealing material which does not contain a component having a food hygiene problem. In a vacuum vacuum container made of stainless steel, a vacuum insulated space is formed between the inner container and the outer container by a vacuum exhaust treatment through the exhaust hole, and the fluorine coating is added to at least one surface of the inner container and the outer container. A metal vacuum double container having a softening point higher than the fluorine paint firing temperature and the degassing temperature at the time of vacuum evacuation, and the exhaust hole being sealed by a low melting glass sealant substantially free of lead. In the metal vacuum double container between the inner and outer containers of stainless steel products, which is a vacuum insulation space through the vacuum exhaust treatment through the exhaust hole, and the fluorine coating is added to at least one surface of the inner and outer containers, The low melting point glass sealant has a softening point higher than the fluorine paint firing temperature and the degassing temperature during vacuum exhaust, and has a thermal expansion coefficient smaller than the thermal expansion coefficient of stainless steel and the coefficient of thermal expansion is 25 × 10 ⁻⁷ / K or less. A metal vacuum double container, wherein a hole is sealed. The method according to any one of claims 1 to 4, A low-melting-point glass sealing material is a metal vacuum double container, wherein the bismuth-based glass is used. The method according to any one of claims 1 to 5, A metal vacuum double container, wherein stainless steel is martensitic stainless steel. 70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 29 wt% of B ₂ O ₃ , ₁ to 15 wt% of SiO ₂ , 0 to 10 wt% of Al ₂ O ₃ , 0 to 10 wt of Cu0 Sealing glass composition comprising a%. 70 to 90 wt% of Bi ₂ O ₃ , 0 to ₂ wt% of ZnO, 5 to 28 wt% of B ₂ O ₃ , ₁ to 15 wt% of SiO ₂ , 0 to 10 wt% of Al ₂ O ₃ , 0.5 to 6 wt of Cu0 Sealing glass composition comprising a%. In the metal vacuum double container according to any one of claims 1 to 6, after degassing by evacuating between the inner and outer containers of the stainless steel product at a temperature lower than the softening point of the low melting point glass sealing material through the exhaust hole, the vacuum is removed. A method of manufacturing a metal vacuum double container, wherein the exhaust hole is sealed by softening or melting the low melting glass sealing material at a temperature equal to or higher than the softening point in an exhaust state. The method of claim 9, A method for producing a metal vacuum double container, wherein the sealing glass composition according to claim 7 or 8 is used as a low melting point glass sealing material.