JPH02265514A - Enamelled double-wall vessel and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable the uniform application of enamel and manufacture of a double-wall vessel uniformly covered with enamel of high adhesion by integrating the neck parts of inner and outer vessels via a drawing process, and maintaining the radius of curvature of the neck section equal to or above the specific value. CONSTITUTION:This enamel covered double-wall vessel 1 comprises inner and outer vessels 2 and 3 integrated with each other at the neck part thereof. The surface the vessel 1 is applied with an enamel layer 7 and the opening 4 of the outer vessel 3 is sealed with a sealing material 8. In order to manufacture the vessel 1, an element plate 15 comprising metal is drawn, thereby forming a cylindrical body 9 having a curved part 17 formed in the vicinity of the peripheral edge 11 thereof. The bottom surface 10 of the vessel 1 is inversely drawn in such a way as not to exceed the peripheral edge 11 and also in such a way as to ensure that the sectional area of the tip of the neck part 13 continuous from the inner vessel 2 to the outer vessel 3 is a circular arc form having a radius of curvature equal to or above 1.5mum. As a result, a double-wall vessel 12 is obtained. By applying the circular form having the aforesaid radius of curvature to the neck part, enamel can be evenly coated. In addition, corrosion and the separation of an enamel layer can be prevented, thereby enabling the manufacture of an enamel covered double wall vessel having good appearance and corro sion resistance.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention is directed to an enamel-coated double coated porcelain coater with excellent heat retention performance, in which an enamel layer is formed on the surface and a gap is provided between the inner container and the outer container. The present invention relates to a method for manufacturing a wall container.

[Prior art] Conventionally, this type of double-walled container was manufactured by
One having a double wall structure described in Japanese Patent No. 481 is known. The manufacturing method for this double-walled container involves fixing the lower end of the outer container to the base, fitting a separate inner container inside the outer container, and welding the upper edges of the inner and outer containers to integrate them. By providing an air gap between the inner and outer containers, it exhibits excellent heat retention and cold retention properties.

However, although these metal coffee cups have a luxurious feel, they have a certain coldness compared to ceramics, have a metallic odor, and give the impression that the taste of the drink changes. There were times when it didn't suit my tastes. To solve this problem, forming an enamel layer on the surface of the double-walled container was proposed in Japanese Patent Application Laid-Open No. 14252-1983.
This is proposed in Publication No. 6, etc. From a practical point of view, by forming an enamel layer on the surface of the container, you can freely color and decorate it, and it also has various benefits such as no metallic odor being transferred to the contents, and dirt and dirt coming off easily and cleanly. benefits have been obtained.

[Problems to be Solved by the Invention] However, in the case of the enameled double-walled container disclosed in JP-A-62-142526, etc., the method for manufacturing the double-walled container requires that the inner container and the outer container be assembled in advance. Since a method is used in which these parts are manufactured separately and then joined at the mouth part by means such as TIG welding or brazing, the shape of the joined part at the mouth part becomes a corner part partially or entirely. Since it is not possible to apply enamel glaze uniformly and sufficiently to these corners, a sufficient layer of enamel cannot be formed on the corners, which may impair the appearance of the corners or the metal materials that make up the double-walled container. will appear. Furthermore, when carbon steel, which has poor corrosion resistance, is used as a constituent material of a double-walled container, there are disadvantages such as corrosion occurring from defective portions of the wax layer.

To solve this problem, it is possible to finish the joint by cutting off, polishing, etc. and then forming an enamel layer, or by wrapping and tightening a protective material made of stainless steel with excellent corrosion resistance around the joint. Methods have been used in which a floating layer is then formed, but each method has the problem of increasing the number of manufacturing steps.

Furthermore, when brazing or TIG welding, brazing metal, which is a different material from the double-walled container or the enamel layer, precipitates on the joint end surface, which reduces the adhesion strength of the enamel glaze at that part, causing the wax to melt. There was also the problem that the layers easily peeled off. Further, especially when double-walled containers are manufactured by TIG welding, an oxide film is formed, which inhibits the formation of an enamel layer, so an oxide film removal step before glazing is essential.

The present invention was made to solve the above problems, and an object of the present invention is to provide a method for manufacturing a double-walled container uniformly coated with a highly adhesive enamel layer.

[Means for Solving the Problems] The manufacturing method of the present invention provides a metal double-walled container in which an inner container and an outer container having an opening formed at the bottom are integrated through a mouth portion with a gap between them. When manufacturing, the tip of the mouth part is formed into an arcuate cross-sectional shape with a radius of curvature of 1.5 mm or more by drawing a material plate, and then an enamel glaze is applied to the surface of this container, and it is fired to form an enamel layer on the surface of the container. The solution is to form.

[By forming the mouth part of the inner container and the mouth part of the outer container into one piece by drawing without welding, and by making the radius of curvature of the cross section of the mouth part 1.3 Inm or more, it is possible to apply a uniform glaze. It is now possible to uniformly apply the enamel glaze to areas where it has been difficult to apply the enamel glaze, and the exposure of the metal material at the mouth area and peeling defects of the enamel layer are prevented.

[Example] The present invention will be described in detail below.

FIG. 4 shows an example of an enameled double-walled container l manufactured by the manufacturing method of the present invention.

This enamel-covered double-walled container l is made by molding an inner container 2 and an outer container 3, which has an opening 4 formed at the bottom and a handle 6 connected to the side, into one body at the mouth part through a gap 5. The surface thereof is coated with an enamel layer 7, and the opening 4 of the outer container 3 is sealed with a sealing member 8.

1 to 3 show an example of a method for manufacturing such an enameled double-walled container l.

First, a material plate 15 made of metal such as iron, stainless steel, or aluminum is drawn into a cylindrical shape to form a cylindrical body 9 with a curved portion 17 formed near the periphery 11, as shown in FIG. . Next, as shown in FIG. 2, the bottom surface IO of the cylindrical body 9 is added so that it does not exceed the peripheral edge 11 of the cylindrical body 9 and has approximately the same shape as the cylindrical inner container 2. The mouth part 1 that continues from the inner container 2 to the outer container 3
3 is reverse drawn so that the cross-sectional curvature radius of the tip is an arc shape of 1.5o+m or more, and as shown in FIG. A double-walled container I2 having a gap 5 interposed between the double-walled container I2 and the double-walled container I2 is obtained. Mouth area 1
If the tip of No. 3 is made into an arc with a radius of curvature of less than 1.5 mm, not only will it be impossible to apply the waxy glaze sufficiently and uniformly. During heating at 800 to 900°C for firing the enamel layer, the difference in coefficient of thermal expansion between the metal materials constituting the inner container 2 and the outer container 2; 3 and the enamel glaze is greatly reflected, and the mouth part 13 This is not preferable because a large strain force is generated in the wafer, which may cause the waxy layer to peel off. Next, a U-shaped handle 6 made of the same material as the double-walled container 12 is connected to the outer periphery of the double-walled container 12 formed here by spot welding, projection welding, or the like.

Thereafter, enamel glaze is applied to the outer surfaces of the inner container 2 and outer container 3, respectively. The enamel glaze to be applied is selected as appropriate depending on the type of material plate, but when the inner container 2 and outer container 3 are made of SPP material, which is the most commonly used steel material for enameling, Since it is assumed that the surface of the steel plate is roughened for the purpose of improving the adhesion of the wax layer 7, oxides such as nickel, cobalt, and copper, which have a lower ionization tendency than iron, are added in a total amount of 1. 5-35
It is preferable to use a glaze containing a degree by weight % because the firing treatment roughens the surface of the steel plate and forms the enamel layer 7 with good adhesion on the surface of the steel plate. The outer surface of the double-walled container 12 herein refers to the surface that does not face the cavity 5, and includes the inside of the inner container 2 and the outside including the handle 6 of the outer container 3. It shows.

Thereafter, this is fired at 800 to 900°C to form the enamel layer 7. Next, a disc-shaped resin sealing member 8 obtained by injection molding is fitted into the opening 4 at the bottom of the outer container 3 to form an enamel-coated double wall having the configuration shown in FIG. A container l is obtained. Note that in order to fit the resin sealing member 8 into the opening 4 of the outer container 3, the sealing member 8 is deformed so as to come into close contact with the curved portion 17 formed in advance at the bottom of the outer container 3. It can be done easily. Also, at this time, the double-walled container 12 on which the crawling layer 7 is formed
For the purpose of increasing airtightness, watertightness, etc. between the sealing member 8 and the sealing member 8, various adhesives may be appropriately applied to the fitting portion. Further, the material of the sealing member 8 is not limited to resin, and may be selected from various materials such as metal, metal with a painted or enameled layer, and rubber. The enameled double-walled container I manufactured in this manner has the mouth portions 13 of the inner container 2 and outer container 3 integrally formed by drawing without curing, and the cross-section of the mouth portion 13 is The radius of curvature is 1.5m
Since the arc shape is larger than m, the enamel glaze can be applied sufficiently uniformly, and the enamel layer 7 with a sufficient thickness can be uniformly formed on the surface.

Next, FIG. 5 shows a second embodiment of the present invention.

In FIG. 5, parts having the same functions as those shown in FIGS. 1 to 4 are designated by the same reference numerals, and detailed explanation thereof will be omitted. The enameled double-walled container l having the structure shown in FIG. 5 is different from the one shown in FIG. At the same time, the gap 5 was evacuated to form a vacuum heat insulating layer 16.

In this example, first, two metal plates are drawn at the same time to form a mouth portion 13 in a row, and an inner container 2 and an outer container 3 are integrally formed with a gap 5 interposed therebetween. Next, a metal sealing member 8a is vacuum-sealed to the opening 4 at the bottom of the outer container 3, and the inside of the cavity 5 is vacuum-insulated @16. As a sealing means for the sealing member 8a, brazing or the like can be used.

To explain this vacuum-to-soil process in detail, a gap is maintained between the peripheral edge 11 of the outer container 3, which is the joint part with the sealing member 8a, and the sealing member 8a, and a solid brazing material 14 is placed between or near the gap.
Set up. Next, in a vacuum heating furnace or the like, for example, 10-"T
600 to 1 by high frequency heating, electron beam heating, or radiation heating using resistance wire.
By heating to 200° C., air is exhausted from the cavity 5 and the vacuum level is maintained at the same level as in the vacuum heating furnace. Further, by heat treatment at a high temperature, the solid brazing material 14 is melted and the opening 4 is sealed. After forming the void 5 into a vacuum heat insulating layer 16 in this way, enamel glaze is applied to the entire surface of this metal double-walled container and fired to form an enamel layer 7 on the outer surface.
form. Then, for the purpose of stabilizing and protecting the bottom, a cap 18 is attached to wrap around the bottom of the double-walled container to form an enameled double-walled container 15. The cap 18 is made of resin or the like, and can be fixed by fitting the curved portion 17 formed at the bottom of the outer container 3 while deforming the cap 18.

By forming the gap 5 between the inner container 2 and the outer container 3 into a vacuum insulation layer in this way, not only a higher insulation effect can be obtained, but also a clean A metal surface is obtained, and a strong enamel layer 7 with higher adhesion can be formed.

Furthermore, since the enameled double-walled container l manufactured in this way has the enameled layer 7 formed on its entire surface,
It becomes highly durable.

Furthermore, in this example, a cap 18 is attached to the bottom of the table, so that it can be prevented from slipping on the table.

In addition, if SPP material specified by JIS is used as a steel material for enamel as a component of the enameled double-walled container shown in FIGS. 4 and 5, Ni will be removed during brazing. Although wax, Cu-Mn wax, Ag wax, etc. can be used, it is known that this brazing material precipitates on the joint end surfaces, reducing the adhesion strength of the wax glaze.

However, by using the manufacturing method of the present invention and adding oxides such as nickel and cobalt, which are metals with a lower ionization tendency than iron, as the enamel glaze, the metal oxides can be oxidized on the surface of the steel sheet. It is now possible to roughen the surface of the steel plate by promoting an oxidation-reduction reaction with iron, making it possible to omit the pickling treatment that was previously essential, reducing manufacturing costs. be able to.

[Effects of the Invention] As explained above, the method for manufacturing an enameled double-walled container of the present invention involves welding the opening of the inner container and the opening of the outer container of the metal double-walled container. The glaze is formed into one piece by drawing a raw material plate, and the radius of curvature of the cross section at the tip of the mouth part is an arc with a radius of 1.5 mm or more, which enables uniform application of the glaze, which was not possible with conventional methods. It is possible to prevent corrosion caused by the exposure of metal materials and peeling due to defects in the waxy layer, which are difficult to prevent with oil. Therefore, it is possible to manufacture an enameled double-walled container that is aesthetically pleasing and has good corrosion resistance.

Furthermore, according to the manufacturing method of the present invention, the opening of the metal double-walled container is integrally formed by drawing, which eliminates the step of joining the inner and outer containers at the upper end of the opening in the conventional method. In addition, cutting off and polishing can also eliminate the need for an acid cleaning treatment process, making it possible to significantly reduce manufacturing costs.

Furthermore, if you manufacture cups etc. using this manufacturing method,
Not only does the cross section of the tip of the mouth part have an arcuate shape with a radius of curvature of 1.5 mm+ or more, but also a sufficiently thick enamel layer is formed, resulting in an extremely smooth mouthfeel during use.

Further, as shown in the second embodiment of the present invention, if the gap formed between the inner container and the outer container is evacuated to form a vacuum insulation layer, a double layer that exhibits higher heat retention performance can be used. You can get a wall container.

Note that in both the examples shown in FIGS. 4 and 5, the inner container 2 and the outer container 3 are integrally molded, but the manufacturing method of the present invention is not limited to this, and only the mouth part 13 is molded. It is not particularly limited as long as it is integrally molded.

For example, as shown in FIG. 6, the upper edge of the inner container 2 formed in the shape of a cylinder with a bottom is bent outward, the folded part 19 is used as the opening part 13, and the peripheral edge 20 of this folded part 19 is separated. The double-walled container 12 may be formed by contact welding to the upper edge 21 of the generally cylindrical outer container 3 made of a body.

Further, as shown in FIG. 7, contrary to FIG. 6, the upper edge of the cylindrical outer container 3 is bent inward to make the folded part 19 the mouth part 13, and the peripheral edge 20 of the folded member 19 is bent inward. The double-walled container 12 may be formed by contact welding to the upper edge 21 of the inner container 2 formed as a separate cylinder with a bottom.

[Brief explanation of drawings]

1 to 3 are schematic cross-sectional views illustrating manufacturing examples of the enamel-coated double-walled container of the present invention in the order of steps, and FIG. 4 is a schematic sectional view of the enamel-coated double-walled container obtained by the manufacturing method of the present invention. FIG. 5 is a schematic sectional view showing one example, FIG. 5 is a schematic sectional view showing a second manufacturing example of the present invention, and FIGS. 6 and 7 are both schematic sectional views showing other manufacturing examples of the heat insulating container. I... Wax coated double wall container, 2... Inner container, 3... Outer container, 4... Opening, 5... Cavity, 7... Wax layer, 12...・Double-walled container, 13... Mouth part, 15... Material board.

Claims (1)

[Claims] When producing a metal double-walled container, which consists of an inner container and an outer container with an opening formed at the bottom separated by a gap and integrated through the mouth, the tip of the mouth is drawn from a material plate. An enamel-coated double-walled container characterized in that the container is formed into an arcuate cross-sectional shape with a radius of curvature of 1.5 mm or more, and then an enamel glaze is applied to the surface of the container and fired to form an enamel layer on the container surface. Production method.