JPH09187368A - Titanium-made rice cooking pan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a titanium-made rice cooking pan which is lightweight and not harmful to living body, and can regularly provide a satisfactory rice cooking state. SOLUTION: In this titanium-made rice cooking pan, the base is formed of titanium or a titanium bas alloy, and the base has a film of a titanium oxide represented by a general formula Tim On (wherein (m) and (n) are integers, n/m$2) formed on at least the pan inner surface part contacting rice or/and the inner lid inner surface part directly contacting steam. Such rice cooking pans include an inner pan for automatic rice cooker, a canteen and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed to a rice cooker widely used for business to general household use, an inner cooker for an automatic rice cooker, a rice cooker for outdoor cooked rice, and the like. The present invention relates to a titanium rice cooker which has excellent heat resistance, is lightweight, and is not harmful to the body.

[0002]

2. Description of the Related Art Rice cookers and inner pots for rice cookers were made of iron in the past, but nowadays they are made of stainless steel due to improvements in alloy processing technology and the development of rice cookers that use electricity or gas sources. Iron-based alloys, aluminum or alloys thereof are widely used as the base material. However,
These base materials have the property of easily rusting if mishandled.For example, when cooking cooked rice mixed with a salt-containing additive, immediately move the cooked rice to another container after cooking. There is a problem that the rust is likely to progress on the pot base material unless the pot is washed with a tap. For this reason, a product has been commercialized in which the inner surface of the pot is coated with a fluorine-based resin, metallic titanium, or the like to prevent rust and prevent burning.

By the way, recently, the influence of metal ions on the human body has become a problem. For example, metal ions such as nickel, chromium, cobalt, and vanadium contained in alloys cause allergic diseases and affect living bodies. It is also regarded as a problem by some experts, that it causes toxicity and that long-term absorption of aluminum ions causes Alzheimer's disease. These metal ion damages have been pointed out from the viewpoint of safety not only when they come into direct contact with the skin such as watches and rings, but also in pot pots which cook food on a daily basis.

[0004]

The metal ions having biotoxicity as described above can be prevented from being eluted by coating the surface of the substrate with a fluororesin or harmless metallic titanium. However, the coating layer secondarily formed by coating the substrate surface with a different substance is
It is inevitable that a peeling phenomenon due to abrasion or thermal shock will occur during a long-term use process, and there is a drawback that the coating effect decreases with time.

An object of the present invention is to provide a rice cooker made of titanium, which is excellent in soaking property, is light in weight, is free from bio-harmfulness and rusting property and is always guaranteed to be deliciously cooked for a long period of time.

[0006]

In order to achieve the above object, a titanium rice cooker according to the present invention has a base material made of titanium or a titanium-based alloy, and at least an inner surface portion of the base material in contact with cooked rice or / And a titanium oxide film represented by the general formula Ti _m O _n (where m and n are integers and n / m ≦ 2) is formed on the inner surface portion of the inner lid that is in direct contact with the steam. What is done is a structural feature.

The rice cooker to which the present invention is applied includes a cooker for cooking cooked rice by direct fire, an inner cooker (including an inner lid) stored in an automatic rice cooker, a portable rice cooker, and others. It is defined as including a container for cooking rice similar to this.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION As a base material constituting the titanium rice cooker of the present invention, pure titanium belonging to JIS standards 1 to 3 or nickel, chromium, cobalt, vanadium, aluminum or the like as an alloy component is substantially used. A titanium-based alloy that does not contain a specific amount is selected. The substrate has a plate thickness of 0.3 to
A plate material having a thickness of 5 mm, preferably 1 to 3 mm is used, and is formed into a desired pot shape by an appropriate processing means such as a spatula drawing process, a spinning process, a pressing process, and a rolling process. Further, when the purpose is an inner pot for a rice cooker, the accompanying inner lid is also processed into the desired shape by processing the same plate material.

The above-mentioned base material is at least a pot inner surface portion in contact with cooked rice, that is, a portion containing rice and water.
Preferably, on the entire inner surface of the container, and in the inner pot of the rice cooker, not only on the inner face of the pot but also on the inner face portion of the inner lid that is in direct contact with steam, the general formula Ti _m O _n (wherein, m and n are integers, A titanium oxide film represented by n / m ≦ 2) is formed. The titanium oxide represented by the above general formula includes titanium dioxide (TiO ₂ ) and titanium suboxide (TiO, Ti
₂ O ₃ , Ti ₃ O ₅ , Ti ₄ O ₇ , Ti ₅ O ₉ ) are included. The specific film forming means for forming the titanium oxide layer on the surface of the base material is that the surface of the base material is pre-pickled, then washed with an organic solvent such as alcohol or ether to be activated, and then under an oxidizing atmosphere. A method of forming a titanium oxide layer and / or a titanium suboxide layer by converting the titanium component in the surface layer of the base material into an oxide by heat treatment or electrochemical treatment is employed. The thickness of the titanium oxide layer to be formed is not particularly limited, but at least 5 μm or more, preferably 30 to 10
The range is 0 μm.

The titanium oxide layer may be formed on the surface of the base material after the plate material is preliminarily processed into the shape of the pot and the inner lid as described above, but it may be formed at the plate material stage before the shape forming. Good. In this case, the film-formed titanium oxide acts as a kind of lubricant and facilitates release from the mold during spatula drawing or pressing. Therefore, there is an advantage that the processing efficiency is improved and the finished surface after processing is good.

The titanium rice cooker according to the present invention formed as described above is not harmful to the human body because titanium or titanium-based alloy which is not harmful to the body is selected as the base material. In addition, it is easy to handle because it is composed of a thin plate of about 1 to 3 mm, using a lightweight titanium base material, and especially when it is formed as a large-scale pot for business use, it can be transported, washed, etc. It is extremely advantageous for operation. Considering from the viewpoint of rice cooking function, titanium or titanium-based alloy as the base material has a relatively low thermal conductivity, so the entire pot is heated uniformly during rice cooking. The coating layer exerts a synergistic effect that further enhances the above functions,
It is possible to obtain a cooked rice state that is excellent in aroma, umami, color and luster, and plumpness. The soaking effect of the titanium oxide layer is presumed to be based on the fact that the titanium oxide layer emits far infrared rays. The titanium oxide layer formed on the surface of the base material is not a secondary coating formed of a different substance, but is an oxide layer integrated with the base material whose material is converted by surface oxidation treatment for a long time. Hard to wear or peel off even when used. Therefore, it is assured that the above-mentioned excellent cooked state is maintained for a long time.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. However, the scope of the present invention is not limited to these examples.

Example 1 (1) Manufacture of an inner pot made of titanium An inner pot of a commercially available electric rice cooker (cooking 1 liter) using a pure titanium plate having a plate thickness of 1.2 mm (JIS standard type 1 equivalent) as a base material. And a spatula was drawn into the same shape as the upper lid. The inner surface of the molded inner pot base material and the outer surface of the inner lid base material were degreased and pickled, then thoroughly washed with alcohol and dried. Then
500 to 650 ° C by heating from outside the molding substrate in the atmosphere
Oxidation treatment was performed at the temperature of 0.5 hours. Both the inner surface of the inner pot and the outer surface of the inner lid, which had been left to cool to room temperature after the oxidation treatment, turned blue, and when measured by X-ray diffraction, TiO ₂ and T
It was confirmed that the film was a titanium oxide film corresponding to i ₂ O ₃ . The thickness of the titanium oxide layer was about 80 μm.

(2) Rice Cooking Experiment In the titanium inner pot prepared as described above and the aluminum alloy inner pot of the same shape (commercial item as a model of this example), 0.4 liters of washed rice and a considerable amount The experiment was repeated in which the water was added under the same conditions and the rice was cooked at the same time by the electric rice cooker. The titanium inner pot was covered with the titanium inner lid manufactured as described above, and the aluminum alloy inner lid was covered with the attached aluminum alloy inner lid. 3 cooked rice at each experimental stage
Name evaluator judged appearance and taste at the same time, whiteness,
The color luster, aroma, umami, and plumpness were evaluated. It should be noted that the evaluation standard was rice cooked in an aluminum alloy inner pot, and the rice evaluated in the titanium inner pot with excellent evaluation was rated "good" and the equivalent was rated "same". The results are shown in Table 1.

(3) Storage state The cooked rice was stored in a pot for 12 hours and 24 hours at room temperature, and then three evaluators sampled it.
As a result, the rice cooked in the titanium inner pot had no change in appearance and no offensive odor compared to the rice cooked in the aluminum alloy inner pot, and the umami taste including fragrance, stickiness, and softness of the core was clear. It was confirmed to be excellent.

(4) Inner pot condition after repeated use The rice was cooked 70 times, and the spatula was scraped off with a spatula after each use, and the titanium oxide film on the inner face of the inner pot was not worn or peeled. There wasn't.

Example 2 (1) Manufacture of a titanium rice cooker Using a pure titanium plate having a plate thickness of 2 mm (JIS standard Class 1 equivalent product) as a base material, it has the same shape as a commercially available cast iron rice cooker (2 liter cook). Spatulated. A substrate having the same material and a thickness of 1 mm was prepared as the inner lid. Each of the molded substrates was degreased, pickled, immersed in a 1% aqueous solution of phosphoric acid, and anodized by applying a voltage of 40V. The surfaces of the rice cooker and the inner lid thus oxidized were both blue-colored, and it was confirmed by X-ray diffraction that they were titanium oxide films corresponding to TiO ₂ and Ti ₂ O ₃ . . The thickness of the titanium oxide layer was about 80 μm.

(2) Rice Cooking Experiment 1 liter of washed rice was placed in a titanium-made rice cooker of the same shape and a cast-iron rice cooker of the same shape (commercially available as a model of this example), and the rice cooker An experiment was repeated in which the heat was adjusted to the same level and the rice was cooked at the same time. In addition, the inner lid,
The titanium rice cooker was provided with the titanium inner lid produced as described above on the lower surface of the commercially available upper lid. The rice cooked at each experimental stage was evaluated in the same manner as in Example 1, and the results are also shown in Table 1.

[0019]

[Table 1]

From the results shown in Table 1, the rice cooked using the titanium rice cooker of the present invention has a scent, umami, and aroma that are higher than those cooked under the same conditions using a commercially available aluminum alloy inner pot or cast iron rice cooker. It was recognized that it was excellent in plumpness. In addition, the storage condition after cooking rice and the material condition after long-term use were also good.

[0021]

As described above, the titanium rice cooker according to the present invention has the following various effects. (1) It is possible to obtain a cooked rice state that is excellent in aroma, umami, color luster, and plumpness. (2) Since titanium or titanium-based alloy, which is not harmful to humans, is selected as the base material, it is not harmful to the human body and there is no danger in terms of safety and hygiene. (3) Since the pot body is made of titanium, it has excellent corrosion resistance and can be steamed and stored as it is even when cooked rice with salt added to the drug is cooked. (4) It is convenient to handle because it is originally made of a lightweight titanium base material and is composed of a thin plate of about 1 to 3 mm, and it is useful for a wide range of rice cooking applications from general household use to business use.
In particular, when it is used as a large pot for business use or as rice cooker or rice cooker for outdoor leisure, it is extremely advantageous for operations such as transportation and washing. (5) Since the titanium oxide layer formed on the surface of the base material is an oxide layer integrated with the base material whose material has been converted by surface oxidation treatment, it does not wear or peel even after long-term use. The above-mentioned excellent cooked state is guaranteed to last for a long time. Even if the coating film peels off, it can be easily regenerated and repaired. (6) Since the molding of the base material is relatively easy, the inner pot of an automatic rice cooker using electricity or gas as a heat source, and other pots of any shape can be easily produced.

Claims (1)

[Claims] 1. The base material is made of titanium or a titanium-based alloy, and the general formula Ti _m O _n (in the formula: , M and n are integers, and n / m ≤ 2
It is. ) A titanium rice cooker characterized by being formed with a film of titanium oxide represented by.