JPS59118121A - Electric rice cooker kettle having heat resistant coating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to a pot for an electric rice cooker having a heat-resistant coating on its outer surface.

[Technical background of the invention]

Conventionally, pots for electric rice cookers were made by press-forming an aluminum plate into the desired shape, and then anodizing the inside and outside with sulfuric acid to improve corrosion resistance.

Thereafter, the inner surface is coated with fluororesin so that the cooked rice that is stuck to it can be easily removed. In addition, recently, in order to save energy by shortening the cooking time, when alumite is processed, the outer surface is finished black using electrolytic coloring, or black paint is applied to efficiently absorb heat rays. be.

[Problems with background technology]

The method of treating the external surface with electrolytic coloring uses sulfuric acid and salt salts as chemicals and performs electrolysis with direct current and alternating current, so washing with water is necessary and removes acids, alkalis, metal ions, etc. in the wastewater. must be treated to prevent pollution, which requires a huge amount of equipment. In addition, electrolytic coloring is not a simple matter in which bath management such as electrolyte composition and pH during treatment is delicate, and accidents such as failure to color due to poor contact with the energized rack are likely to occur. In addition, the method of applying black paint has a low heat resistance temperature, and the outer surface temperature during cooking (300 to 400
℃), making it impractical.

[Purpose of the invention]

The purpose of this invention is to form a coating on the outer surface of a steel coated with an electrolytic method such as alumite or electrolytic coloring, which has excellent heat resistance, scratch resistance, water resistance, and good heat ray absorption and heat storage.

[Summary of the invention]

A coating layer consisting of aluminum phosphate and a heat-resistant pigment or silicate powder and a heat-resistant pigment, a silicone resin, a heat-resistant pigment, a silicone resin, colloidal silica, and a heat-resistant pigment was formed on the outer surface of the pot.

[Embodiments of the invention]

Hereinafter, the present invention will be described based on embodiments with reference to the drawings.

Figure 1 is a partially cutaway sectional view of a pot for an electric rice cooker, where (1) is the pot body made of press-formed aluminum, (2a) and (2b) are the alumite coating that covers the inner and outer surfaces, respectively. , (3) is the alumite coating on the inner surface (
2a), and (4) is a heat-resistant coating layer formed on the alumite coating (2b) on the outer surface. This heat-resistant coating layer (4) consists of aluminum phosphate, sodium silicate, or silicone resin and a heat-resistant pigment.

Next, a method for forming the heat-resistant coating layer (4) will be described.

(1) Aluminum sheet, anodized aluminum sheet, or fluororesin-treated aluminum sheet,
Or make a pot by press-molding an aluminum sheet that combines them.

This pot is thoroughly degreased with a neutral or weakly alkaline degreaser and coated with the paint shown in Table 1.

Table 1 After 2-stirring with a Zeball mill, apply a layer of about 10-20 μm to the outside of the pot using a spray gun, air dry for 5-10 minutes, and pre-dry in a drying oven at 130-170°C for 5-50 minutes.
After 15 minutes, the temperature of the furnace was gradually raised to 300'O and baked for about 30 minutes to form a hard black coating layer.

(2) Paint a sample prepared in the same manner as in Example 1 with the paint shown in Table 2.

Table 2 Stir 2 batches with a Zeball mill, apply about 10 to 20 μm on the outside surface of the pot with a spray gun, air dry for 5 to 10 minutes,
Dry with 5 to 15 molecules in a drying oven at 0 to 170°C, then gradually raise the temperature of the oven to 270'C and bake for about 30 minutes to form a hard black coating layer.

(3) Paint the paint shown in Table 3 on the sample prepared in the same manner as in Example 1.

Table 3: After thoroughly kneading the above material with a roll, diluting it with benzene to make it easier to spray paint it, apply it to the outside surface of the pot to a thickness of about 10 to 20 μm with a spray gun, and after thoroughly air-drying it, paint it at 150°C for 15 minutes. Pre-dry in a drying oven and gradually dry for 30 minutes.
The temperature was raised to 0°C and baked for 20 minutes to form a black coating layer.

(4) Apply the paint shown in Table 4 to the sample prepared in the same manner as in Example 1. In other words, after thoroughly kneading the above material with a roll, spray it onto the outer surface of the pot to a thickness of about 10 to 20 μm, and thoroughly dry in the air. After that, it is baked at 170°C for 20 minutes to form a black coating layer.

Next, the data obtained by measuring the heat ray absorption coefficient of the sample in Example 1.2.3.4 above are shown in the curves (
6) to (9). The vertical axis shows the emissivity of heat rays (equal to the absorption part), and the horizontal axis shows the wavelength of infrared rays. The device is an improved version of the JASCO infrared spectrometer, which heats the blackbody and sample and records the heat radiation intensity on a chart for comparison with the blackbody (100%) Z sample. In these figures, the higher the graph is, the better the radiation and absorption of heat rays is. If the vertical axis is 100, the heat rays of that wavelength are
Absorbs 0%.

Figure 6 shows the heat radiation (absorption) characteristics of black alumite with curve (9), but the radiation (absorption) is clearly worse on the short wavelength side compared to the coating films shown in Figures 2 to 5. ing. Since the heater that heats the pot mainly uses wavelengths of about 2 to 10 μm, it is important for the coating to absorb relatively short wavelengths. There is almost no difference between the four types of coating films mentioned above.
All have excellent emissivity (absorption rate) in the range of 2 to 10 μm.

From the above, if the sample is heated to 250℃,
It can be seen that the coating layer made of paint film absorbs heat rays better than black alumite. Also, if the heating temperature deviates (over or below 250°C), this graph will simply shift in parallel, so within the operating temperature range of the pot, black alumite is always better than black alumite. It has excellent heat absorption. Table 5 shows the results of a comparison of long-term durability performance between black alumite and paint.

(North I bottom margin Table 5 Note) ◎Very good ○Excellent△Practically sufficient ×Cannot be used Equal to or better than Might.

In addition to the above-mentioned resins, heat-resistant resins such as polyimide resin and PP8 resin can also be used as the binder. Further, the heat-resistant pigment to be incorporated into the coating film may be oxides, nitrides, carbides, etc. of various transition metals with good infrared emissivity.

〔Effect of the invention〕

As mentioned above, when a heat-resistant coating layer made of a heat-resistant paint containing aluminum phosphate, sodium silicate, silicone resin, or other binders is formed on the outer surface of an electric rice cooker pot, it absorbs heat rays better than conventional pots. It is possible to make products with excellent strength and durability.

[Brief explanation of the drawing]

Figure 1 is a partially cutaway cross-sectional view of a pot for an electric rice cooker, Figures 2 to 5 are graphs showing the heat ray absorption rate of the pot with a heat-resistant coating layer formed thereon, and Figure 6 is the heat ray absorption rate of a blackbody sample. This is a graph of (1): Pot body (2a), (2b): Alumite coating 1 (3)': Fluorine resin coating (4
): Heat-resistant core layer electric 1 figure 'I2 figure → 7II length of the edge of the edge C no e installation)

Claims (1)

[Scope of Claims] 1) Heat-resistant, characterized in that it is made of an aluminum member, has an alumite or fluororesin, or a combination thereof layer on the inner surface, and has a heat-resistant coating layer formed from a heat-resistant paint on the outer surface. A pot for an electric rice cooker with a coating. 2) Claim 1, characterized in that the heat-resistant coating layer formed on the outer surface is made of aluminum phosphate and a heat-resistant pigment.
A pot for an electric rice cooker having a heat-resistant coating as described in 1. 3) A pot for an electric rice cooker having a heat-resistant coating according to claim 1, wherein the heat-resistant coating layer formed on the outer surface is made of sodium silicate and a heat-resistant pigment. An electric rice cooker pot with a protective coating. 5) The heat-resistant coating layer formed on the outer surface is made of silicone resin.