JP2000333848A - Stainless steel vacuum double container and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stainless steel vacuum double container, with which the dirt or smell of a fur is hardly left and dirt or smell can be easily removed by washing with water, improved in a heat insulating effect and improved in beautiful appearance as well. SOLUTION: An inner container 1 and an outer container made of stainless steel are double coupled while providing a gap and an interval between these inner and outer containers 1 and 2 is used as a vacuum space 3. As for such a stainless steel vacuum double container, the surface of the inner container 1 for storing a content liquid is formed into surface state having the small degree of roughness with surface roughness Rz<4.0 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stainless steel vacuum double container used for a portable stainless steel bottle or a thermos for stationary use, and a method for producing the same.

[0002]

2. Description of the Related Art A portable stainless steel bottle used for keeping a liquid beverage warm has an inner surface of an inner container of a vacuum double container, which is subjected to electrolytic polishing to remove stains such as welding scales.
Corrosion resistance is improved. In a conventional portable stainless steel bottle, SUS304 is used as stainless steel, and the surface treatment of the inner container surface is performed by electrolytic polishing using an electrolytic solution containing phosphoric acid and sulfuric acid as main components.

[0003] As a surface treatment of the inner container surface,
Fluororesin has been coated for the purpose of "easy to get dirty" and "easy care".

[0004]

However, the surface treatment by the conventional electrolytic polishing has a surface roughness Rz of about 4.
5 μm, and when observed microscopically, FIG.
(A) As shown in FIG. 3, there are countless crater-shaped or void-shaped recesses a on the inner surface of the inner container. For this reason, the fine particle component in the beverage liquid enters the concave portion a,
It is easy to adhere to it, and it is difficult to remove it. Dirt such as water scale, coffee traces, tea astringent traces, etc. remains on the inner container surface, and odor remains, which is difficult to remove by washing with water or the like. There is a problem that is.

[0005] In addition, it is difficult to achieve the objectives of the conventional surface treatment with a fluorine-based resin coating, which are "hard to stain" and "easy care" in reality. That is, as shown in FIG. 2 (b) and FIG. 4, when the microscopic observation is carried out by the influence of the surface properties of the fluororesin itself and the unevenness of the inner container surface formed by blasting before coating, Innumerable voids or crater-shaped recesses b are present on the resin surface. FIG. 4 clearly shows the void-shaped recess b. Fluorinated resins are excellent in water repellency and therefore exhibit their performance in the early stage of use, but when the beverage is put into the container and used several times, the water repellency drops sharply. The reason is that, similarly to the case of the conventional electropolishing surface treatment, the fine particle component in the beverage enters the concave portion b and adheres thereto. Also in this case, there is a problem that dirt such as water scale remains on the inner container surface and odor remains, and it is difficult to remove the smell.

The present invention solves the above-mentioned problems of the prior art, so that dirt and odor such as water scale are hardly left, and dirt and odor can be easily removed by washing with water. An object of the present invention is to provide a vacuum double container made of stainless steel and a method for producing the same.

[0007]

According to the present invention, in order to attain the above object, a stainless steel inner container and an outer container are double-combined with a gap provided therebetween, and a vacuum space and a vacuum space are provided between the inner and outer containers. In the stainless steel vacuum double container prepared above, the surface of the inner container into which the content liquid is placed has a surface roughness Rz of 4.0 μm.
It is characterized in that it is formed in a surface state in which the degree of roughness of less than m is small.

In the above invention, the surface roughness Rz is preferably 1.5 μm or less, and more preferably the surface roughness Rz is 0.7 μm or less.

In the above invention, it is preferable that the stainless steel, which is the material of the inner container, is made of SUSXM7 or Cu similar thereto, because it is easy to reduce the surface roughness Rz.

[0010] According to the above invention, since the inner container surface is formed in a surface state having a gentle unevenness and a surface roughness Rz of less than 4.0 µm, the fine particles in the beverage liquid are formed in the concave portions formed on the surface. Are hard to enter and remain, and even if they enter the recess, they are easily removed by washing with water or the like. As the surface roughness Rz becomes smaller, the depth of the recess becomes smaller, and when the surface roughness Rz becomes 1.5 μm or less, the adhesion of the fine particles in the beverage is almost certainly prevented, and very easily. The fine particles can be removed by washing or the like, and a surface state that can be visually regarded as a mirror surface can be obtained. Further, when the surface roughness Rz is 0.7 μm or less, the adhesion of fine particles in the beverage can be reliably prevented, and the surface state becomes a substantially smooth surface with almost no irregularities and a perfect mirror surface.

Therefore, according to the present invention, it is possible to prevent the fine particles in the beverage from adhering to the inner container surface and to easily remove the fine particles by washing with water. The problem of odor caused by water can be solved, and dirt and the like can be easily removed by ordinary washing work such as washing with water.

Further, according to the present invention, the inner container surface can be made a glossy surface, a mirror surface or a surface close to the mirror surface, so that the aesthetic appearance can be improved and the internal liquid amount can be reduced. You can easily find out.

Further, according to the present invention, the reflectivity of the inner container surface can be improved. As a result, the heat radiation effect can be improved, and the heat retention efficiency of the content liquid can be increased.

When the inner container is formed by welding, as shown by the imaginary lines with Q and R in FIG. 1, the corrosion resistance of the welded portion can be improved.

In addition to the constitution of the present invention, the inner and outer peripheral surfaces of the mouth of the vacuum double container have a surface roughness Rz of less than 4.0 μm (preferably 1.5 μm or less, optimally 0.7 μm or less). If the surface is formed with a small degree of roughness, the corrosion resistance of the welded portion of the mouth and the threaded portion on the inner and outer circumferences can be improved.

In manufacturing the stainless steel vacuum double container of the present invention, the inner container surface treatment step can be performed by various methods, for example, electrolytic polishing while performing mechanical polishing using abrasive grains. , A two-stage polishing method in which electrolytic polishing is performed after mechanical polishing using abrasive grains, and a mechanical polishing method in which mirror polishing is performed by ultra-precise mechanical polishing.

The electrolytic polishing method used in the inner container surface finishing step may be performed for a longer time than in the conventional method. Further, it is preferable to improve the conventional electrolytic polishing method and adopt an electrolytic polishing method using an electrolytic solution mainly containing phosphoric acid, since the surface finish with the above surface roughness can be performed in a relatively short time. In addition, as stainless steel,
When SUSXM7 was selected and the surface was finished by an electrolytic polishing method using an electrolytic solution mainly containing phosphoric acid, a mirror-finished surface could be easily obtained in a relatively short time.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Two embodiments of the present invention will be described specifically with reference to the drawings.

(Example 1) FIG. 1 shows a vacuum double container made of stainless steel used for a portable stainless steel bottle. An inner container 1 and an outer container 2 are double-combined, and a vacuum insulation space is provided between them. 3.

The inner container 1 and the outer container 2 are both SUS304
(18Cr-8Ni) and welded at the mouth 4. P indicates a mouth weld. Inner container 1 of mouth 4
A screw 5 that is screwed with a mouth member (not shown) is formed, and a screw 6 that is screwed with a lid (not shown) is formed in the outer container 2 of the mouth 4. Further, an opening 8 for vacuum suction is provided in the outer container 2 at the bottom 7, and the vacuum heat insulating space 3 is evacuated through the opening 8. Thereafter, the opening 8 is joined to the sealing plate 9 by the outer container 2. Thus, the vacuum state is maintained.

The surface of the inner container 1, that is, the inner surface of the vacuum double container has a gentle uneven shape and a surface roughness Rz of 1.4 μm. The surface roughness Rz indicates "ten-point average roughness" defined in "JIS B 0601" as is well known.

In this embodiment, in order to form the surface state of the inner container 1 as described above, the inner and outer containers 1 and 2 are integrated by welding, and then the vacuum insulation space 3 is brought into a vacuum state.
After the opening 8 is sealed with the sealing plate 9, in the next electrolytic polishing step, electrolytic polishing using a phosphoric acid-based electrolytic solution different from the conventional method is performed as shown in FIG.

That is, the vacuum double container is immersed in the electrolytic solution 12 with the mouth 4 turned down to a position near the upper part of the shoulder 10, and the electrode 11 is inserted into the inner container 1. , Electrolytic polishing of the entire surface of the inner container 1 and the surface of the outer container 2 at the mouth portion 4 and the shoulder portion 10 is performed.

As shown in FIG. 2 (c), the surface of the inner container 1 and the surface of the outer container 2 on which the electrolytic polishing has been performed by this electrolytic polishing have a surface state that can be visually regarded as a mirror surface. became.

(Embodiment 2) As described above, the inner container 1 is
In order to further reduce the surface roughness Rz with respect to the one formed in S304, various experiments were performed by increasing the electropolishing time or changing the composition of the electrolytic solution, but the surface roughness Rz was reduced to 0.7 μm. It was difficult to do the following (it is possible by employing the composite polishing method or the two-step polishing method described in the section of "Means for Solving the Problems"). Research into the cause reveals that SUS304 has a point that the surface of the material becomes matte when expanding and drawing for forming the shape of the inner container 1, and the unevenness is not sufficiently removed even by electrolytic polishing. found.

Therefore, the material of the inner container 1 was changed to SUSXM
7 (18Cr-13Ni-3.5Cu) was used to form an inner container 1 having the same shape and structure as in Example 1 and subjected to the same electrolytic polishing. In this embodiment, the outer container 2 is also made of SUSXM7, but the outer container 2 may be made of SUS304. Also SUSXM
Reference numeral 7 denotes a stainless steel characterized in that Cu is added. However, the amount of Cu added is not limited to 3.5% by weight, and a similar stainless steel to which Cu is added may be used. It is.

According to this embodiment, as shown in FIGS. 2 (d) and 5, the inner container 1 has a smooth surface with almost no irregularities and a perfect mirror surface, and the surface roughness Rz is reduced. It was 0.6 μm. This is considered to be because the amount of martensite transformation that occurs when a strong working force (expansion and drawing) is applied to the austenitic stainless steel is small, so that the material surface is unlikely to have a matte state.

(Comparison between Conventional Example and Example) Table 1 shows the results of surface treatment by conventional electrolytic polishing (conventional example 1), those of conventional fluorine resin coating (conventional example 2), The results of measuring the surface roughness of the inner container surface for each of Example 1 and Example 2 are shown. The surface roughness Ra and the surface roughness Rmax are “center line average roughness” and “maximum height” defined in “JIS B 0601”, respectively.

[0029]

[Table 1]

[0030]

According to the present invention, a stainless steel vacuum pump which is not easily left with dirt and odor such as water scale, can easily remove dirt and odor by washing with water, has an excellent heat retaining effect, and is also excellent in aesthetic appearance. A heavy container can be provided.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an example of a vacuum double container made of stainless steel.

FIGS. 2A to 2D show a conventional example and an embodiment of the present invention.
Sectional drawing which shows the cross-sectional shape of the inner container surface typically compared with FIG.

FIG. 3 is a diagram showing the inner container surface of Conventional Example 1 at a magnification of 500 times.

FIG. 4 is a diagram showing the inner container surface of Conventional Example 2 at a magnification of 500 times.

FIG. 5 is a diagram showing the inner container surface of Example 2 at a magnification of 500 times.

FIG. 6 is a conceptual diagram showing an example of electrolytic polishing.

[Explanation of symbols]

 1 inner container 2 outer container 3 vacuum insulation space

Claims (6)

[Claims] 1. A stainless steel vacuum double container in which a stainless steel inner container and an outer container are double-combined with a gap provided, and a vacuum space is provided between the inner and outer containers.
The surface into which the content liquid of the inner container is filled has a surface roughness Rz of 4.0.
A stainless steel vacuum double container formed in a surface state having a small degree of roughness of less than μm. 2. The stainless steel vacuum double container according to claim 1, wherein the surface roughness Rz is 1.5 μm or less. 3. The stainless steel vacuum double container according to claim 2, wherein the surface roughness Rz is 0.7 μm or less. 4. The stainless steel used for the inner container is made of SU.
The stainless steel vacuum double container according to any one of claims 1 to 3, wherein SXM7 or Cu similar thereto is added. 5. The vacuum double container according to claim 1, wherein the inner and outer peripheral surfaces of the mouth portion are formed in a surface state having a surface roughness Rz of less than 4.0 μm with a small degree of roughness. Stainless steel vacuum double container. 6. A method for producing a stainless steel vacuum double container according to any one of claims 1 to 4, wherein the surface treatment step of the inner container surface uses an electrolytic solution mainly composed of phosphoric acid. A method for producing a stainless steel vacuum double container, which is performed by electrolytic polishing.