JP5879755B2 - Heating cooker, method for producing the same, and method for producing cooking utensils - Google Patents

Description

  The present invention relates to cooking utensils such as cooking dishes and cooking containers, and heating cookers such as microwave ovens, microwave ovens, and grills.

  2. Description of the Related Art In a cooking device that cooks food by storing the food to be cooked in a cooking chamber, dirt such as oil or food residue from the food to be cooked adheres to the wall surface of the cooking chamber. For this reason, conventionally, it has been common to apply organic paints on the wall surface of the cooking chamber in order to make it difficult for dirt to adhere to the wall and to easily wipe off the attached dirt with a cloth or the like. As the organic paint, a silicone paint having high temperature and heat resistance is applied in a microwave oven or a grill where the cooking chamber is heated. Also, in microwave ovens, acrylic, urethane, silicone, and fluorine paints are used as organic paints because the cooking chamber does not become as hot as a microwave oven (for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-83027

  However, such organic paints have a problem that the coating film is easily damaged, and it is desired to reduce the adhesion of dirt and to improve the ease of wiping off the adhered substances, that is, to further improve the non-adhesiveness and the cleaning property. It had been.

  Therefore, in view of the above problems, the present invention provides a cooking utensil and a heating cooker that have high hardness, are not easily scratched, and have non-adhesiveness to which dirt is difficult to adhere, and are easy to wipe off dirt and have excellent cleanability. , With a common purpose.

  In the invention of claim 1, by forming a ceramic layer mainly composed of particles having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material, and it has high hardness and scratches. It is possible to provide a cooking utensil that is difficult to stick and that is difficult to adhere to dirt. In addition, since the ceramic layer does not contain organic compounds, the hardness and non-adhesiveness do not decrease even at high temperatures, and dirt can be easily wiped off by the non-adhesive property. It also eliminates the problem of scratching and scratching.

  Moreover, by making the film thickness of the base coating film layer 35 μm or less and the film thickness of the top coating layer 30 μm or less, the occurrence of fine cracks generated on the surface of the ceramic layer is suppressed, and in the tape peeling test It is possible to suppress the granular peeling phenomenon of ceramics, and by making the thickness of the base coating layer 5 μm or more, it is possible to conceal the base material and obtain a good appearance, and the thickness of the top coating layer By setting the thickness to 3 μm or more, roughness of the surface of the ceramic layer can be suppressed while concealing the base coating layer and maintaining a good appearance.

Moreover, generation | occurrence | production of the crack in the surface of a ceramic layer can be suppressed by heating up to 120 degreeC or 150 degreeC over 3 minutes after application | coating of a top coating layer. Moreover, the adhesiveness of a ceramic layer improves after that by baking at 120-250 degreeC for 5 minutes or more, and the granular peeling in a tape peeling test can be eliminated. The ceramic layer completed by firing can withstand a temperature higher than the firing temperature and dissolve the organic compound as long as it is below the heat-resistant operating temperature of the components of the base coating layer, top coating layer, or base material. There is no outbreak. In addition, since only moisture is evaporated during firing, no toxic gas is generated, and there is no problem in terms of safety, environment, and firing is possible at low temperatures, so that the energy consumption of the firing furnace can be reduced.

  In the invention of claim 2, by adding an inorganic component pigment to the base coating layer and coloring it, the presence or absence of coating on the surface of the base material can be easily understood. Visible when it is too thick or too thin. Moreover, the heat resistance of the ceramic layer can be maintained.

  In the invention of claim 3, by making the top coating layer transparent, the interface between the base coating layer and the top coating layer can be easily observed, and the film thickness is too thick when the top coating layer is applied. Or when it is too thin. Furthermore, when the top coating layer is thin, roughness occurs on the surface of the ceramic layer. If the top coating layer is too thick, the ceramic layer becomes more transparent. The film thickness of the layer and the film thickness of the ceramic layer can be visually confirmed. Further, the surface of the ceramic layer becomes a transparent glossy surface, and the appearance quality is improved.

  In the invention of claim 4, the top coating layer glitters in a granular form, and the interface between the base coating layer and the top coating layer can be more easily observed. Further, the appearance quality of the ceramic layer is further improved.

In the invention of claim 5, in the cooking chamber or cooking utensil of the heating cooker, the ceramic layer is not easily peeled off from the base material while maintaining the above-described effects, so that the base material and the ceramic layer are in close contact with each other. Can increase the sex.

In invention of Claim 6, when foreign materials, such as dirt, refer to the surface of a front frame, it can wipe off easily. Also, even if the carbonized solid matter fixed by heating in the heating cooker is scraped off with a scrubber or a spatula, the surface of the front frame is less likely to be scratched and the surface of the front frame is deformed because it can be easily removed. It becomes difficult. Thereby, the clearance dimension of a door and a front frame can be maintained stably, and the problem that the difference with the temperature in the actual heating cooking chamber with respect to the setting temperature as a heating cooker becomes large can be solved.

In the invention of claim 7 , by forming a ceramic layer mainly composed of particles having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material, and it has high hardness and scratches. It is possible to provide a casing for a heating cooker that is difficult to stick and is less likely to adhere to dirt. In addition, since the ceramic layer does not contain organic compounds, the hardness and non-adhesiveness do not decrease even at high temperatures, and dirt can be easily wiped off by the non-adhesive property. It also eliminates the problem of scratching and scratching.

  Further, by setting the thickness of the ceramic layer to 8 to 65 μm, cracks are hardly generated in the ceramic layer, and the base material is not seen through. However, since the inner surface of the cooking chamber has no hindrance in appearance even if the concealability of the base material is reduced, a ceramic layer is formed with a thinner film thickness than the other surfaces, thereby The amount used can be reduced.

In the invention of claim 8 , the end face and the unevenness of the hole are in an environment where cracks are likely to occur in the ceramic layer, but the ceramic formed on the surface of the base material in the inner surface of the cooking chamber including the hole and the unevenness By making the film thickness of the layer thinner than the other surface, it is possible to obtain an effect of making it difficult for cracks to occur in the ceramic layer.

In the invention of claim 9 , by forming a ceramic layer mainly composed of particles having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material, and the scratches are high in hardness. It is possible to provide a cooking utensil that is difficult to stick and that is difficult to adhere to dirt. In addition, since the ceramic layer does not contain organic compounds, the hardness and non-adhesiveness do not decrease even at high temperatures, and dirt can be easily wiped off by the non-adhesive property. It also eliminates the problem of scratching and scratching.

  Moreover, by making the film thickness of the base coating film layer 35 μm or less and the film thickness of the top coating layer 30 μm or less, the occurrence of fine cracks generated on the surface of the ceramic layer is suppressed, and in the tape peeling test It is possible to suppress the granular peeling phenomenon of ceramics, and by making the thickness of the base coating layer 5 μm or more, it is possible to conceal the base material and obtain a good appearance, and the thickness of the top coating layer By setting the thickness to 3 μm or more, roughness of the surface of the ceramic layer can be suppressed while concealing the base coating layer and maintaining a good appearance.

  In addition, by adding an inorganic pigment to the base coating layer and coloring it, it becomes easy to determine whether the base material surface has been painted. Visible when it is too much. Moreover, the heat resistance of the ceramic layer can be maintained.

  In addition, the amount of the pigment added to the top coating layer is less than the amount of the pigment added to the base coating layer, or the pigment is not added to the top coating layer. The boundary surface with the top coating layer can be easily observed to some extent, and can be visually recognized when the film thickness is too thick or too thin when the top coating layer is applied.

Furthermore, the ceramic layer completed by firing can withstand a temperature higher than the firing temperature as long as it is not higher than the heat-resistant use temperature of the component of the ceramic layer or the component of the base material, and no gas is generated due to dissolution of the organic compound. In addition, since only moisture is evaporated during firing, no toxic gas is generated, and there is no problem in terms of safety, environment, and firing is possible at low temperatures, so that the energy consumption of the firing furnace can be reduced.

  Further, not only in actual use, but also when subjected to heating exceeding the maximum usable temperature, there is almost no gas generation as in the decomposition of the organic compound, and safety is improved.

  Moreover, even if the heat receiving temperature of the ceramic layer reaches 230 ° C. or higher, it is possible to withstand the practical heat resistance temperature as a cooking utensil without reducing the hardness of the surface of the ceramic layer.

In the invention of claim 10 , even a base material using an iron-based steel material is not used exceeding the heat resistance temperature of the base material, and the ceramic layer is mainly made of ceramics. No gas is generated.

  According to the first aspect of the present invention, it is possible to provide a cooking utensil that has high hardness, is hardly scratched, has non-adhesiveness, and is easy to wipe off dirt, and has excellent cleanability. In addition, it is possible to provide a cooking utensil that suppresses the occurrence of cracks on the surface of the ceramic layer, suppresses the granular peeling phenomenon of the ceramic, maintains good appearance, and suppresses the roughness of the surface of the ceramic layer.

  Furthermore, the occurrence of cracks on the surface of the ceramic layer can be suppressed, the adhesion of the ceramic layer can be improved, and the granular peeling in the tape peeling test can be eliminated. In addition, it can withstand temperatures higher than the firing temperature, no gas is generated due to dissolution of organic compounds, and there are no safety and environmental problems, and energy consumption of the firing furnace can be reduced.

  According to the invention of claim 2, the presence or absence of coating on the surface of the base material can be easily understood, and the film thickness can be visually recognized when the base coating film layer is applied. Moreover, the heat resistance of the ceramic layer can be maintained.

  According to the invention of claim 3, the boundary surface between the base coating layer and the top coating layer can be easily observed, and the film thickness of the top coating layer and the thickness of the ceramic layer can be visually confirmed. Become. Further, the surface of the ceramic layer becomes a transparent glossy surface, and the appearance quality can be improved.

  According to the invention of claim 4, the boundary surface between the base coating layer and the top coating layer can be more easily observed, and the appearance quality as a ceramic layer can be further improved.

According to the invention of claim 5 , it is possible to provide a cooking chamber or a cooking utensil with improved adhesion between the base material and the coating film.

According to the invention of claim 6 , it is possible to provide a front frame of a heating cooker that has high hardness, is hard to be scratched, has non-adhesiveness, and is easy to wipe off dirt and excellent in cleanability. And the front frame can be stably maintained.

According to the invention of claim 7 , it is possible to provide a casing of a heating cooker that has high hardness, is not easily scratched, has non-adhesiveness, and is easy to wipe off dirt and excellent in cleanability. It is possible to reduce the amount of paint used without causing cracks in the layer and without seeing through the base material.

According to invention of Claim 8 , the effect which makes a ceramic layer hard to generate | occur | produce a crack can be acquired.

According to the ninth aspect of the present invention, it is possible to provide a cooking utensil that has high hardness, is not easily scratched, has non-adhesiveness, and is easy to wipe off dirt, and has excellent cleanability. In addition, it is possible to provide a cooking utensil that suppresses the occurrence of cracks on the surface of the ceramic layer, suppresses the granular peeling phenomenon of the ceramic, maintains good appearance, and suppresses the roughness of the surface of the ceramic layer. Furthermore, the presence or absence of coating on the surface of the base material can be easily understood, and the film thickness can be visually recognized when the base coating layer is applied. Moreover, the heat resistance of the ceramic layer can be maintained. In addition, the boundary surface between the base coating layer and the top coating layer can be easily observed to some extent, and the thickness of the top coating layer and the thickness of the ceramic layer can be visually confirmed.

  In addition, it can withstand temperatures higher than the firing temperature, no gas is generated due to dissolution of organic compounds, and there are no safety and environmental problems, and energy consumption of the firing furnace can be reduced.

  Moreover, the cooking utensil which improved safety | security can be provided not only at the time of actual use but also when it receives the heat exceeding the highest usable temperature.

  Moreover, it becomes possible to endure the practical heat-resistant temperature as a cooking appliance, without reducing the hardness of the ceramic layer surface.

According to the invention of claim 10 , there is provided a cooking utensil that is not used beyond the heat-resistant temperature of the base material even if it is a base material using iron-based steel, and that no gas is generated due to dissolution of the organic compound. Can be provided.

It is a perspective view of the state where the door of the microwave oven common to each embodiment of the present invention was opened. It is a perspective view of the square plate attached to a microwave oven same as the above. It is a perspective view of the baking dish attached to a microwave oven same as the above. It is a perspective view of the grill net attached to a microwave oven same as the above. It is an expanded sectional view of the coating film by the same application same as the above. It is an expanded sectional view of the coating film by 2 times application same as the above. It is an expanded sectional view of the coating film in 1st, 3rd, 4th, 6th embodiment of this invention. It is an expanded sectional view of the coating film in 2nd, 3rd, 4th, 6th embodiment of this invention. It is an expanded sectional view of the coating film in the 5th, 6th embodiment of this invention.

  Hereinafter, preferred embodiments of the heating cooker according to the present invention will be described in detail with reference to the accompanying drawings.

(1) Basic Configuration Common to Each Embodiment FIG. 1 shows a microwave oven 1 common to each embodiment. In the microwave oven 1 as a cooking device, a cooking chamber 11 having only a front surface (front) opened in a cooking chamber 2 serving as a main body, and an object to be cooked (not shown) is accommodated in the cooking chamber 11. It is configured. On the inner wall surface of the cooking chamber 11, a coating film 12 made of an inorganic material not containing an organic compound mainly composed of fine powder of alumina ceramic is applied and formed over the entire surface. That is, the coating film 12 is formed on all surfaces except the opening surface of the cooking chamber 11, that is, the bottom surface, the left surface, the right surface, the back surface, and the top surface. Moreover, the door 16 which covers the front surface of the cooking chamber 11 is provided in the front side of the heating cooking chamber 2 so that opening and closing is possible, and the coating film 12 is formed also on the front edge surface of the heating cooking chamber 2 which contacts the inner edge surface of the door 16. doing.

  Further, for example, a heater 8 as a heating unit is provided in the upper part of the cooking chamber 11, and a microwave generator 9 as another heating unit is incorporated in the cooking chamber 2. It becomes the structure which heats the to-be-cooked object accommodated in the cooking chamber 11 with the radiant heat of this and the microwave from the microwave generator 9. FIG.

  In the cooking chamber 11 of the microwave oven 1, as a cooking utensil for storing the food to be cooked, the square plate 13 shown in FIG. 2, the baking plate 14 shown in FIG. 3, and the baking shown in FIG. 4. A net 15 or the like can be attached. As a cooking dish, each of the square dish 13 and the grilled plate 14 is formed in a tray shape by a flat bottom portion 4 on which an object to be cooked is placed and a frame-like portion 5 rising from the periphery of the bottom portion 4. In addition, the grill 15 is formed by combining a plurality of rods, and includes a net-like placement unit 6 on which an object to be cooked is placed, and a leg 7 that extends below the placement unit 6. . A coating film 12 made of an inorganic material not containing an organic compound mainly composed of fine powder of alumina ceramic is also formed on the surface of these cooking utensils. Also, the coating film 12 is formed on the inner surface facing the cooking chamber 11 with respect to the door 16 of the cooking chamber 11.

  As shown in FIG. 5, the coating film 12 serving as a ceramic layer is obtained by applying a liquid 22 in which an inorganic material not containing an organic compound mainly composed of fine powder 21 of alumina ceramic is dissolved to the surface of a base material 31. It is formed by drying. The fine powder 21 of alumina ceramic has a particle size of 100 nm or less, preferably 50 nm or less. As the liquid 22 for dissolving it, a liquid which does not leave an organic compound after evaporation, for example, water, alcohol or other suitable solvent is used.

  In forming the coating film 12, in addition to the one-time coating as shown in FIG. 5, the two-time coating as shown in FIG. 6 is possible. Although details will be described later, the formation of the coating film 12 is adjusted to a thickness of 10 to 50 μm if it is applied once as shown in FIG. 5. Moreover, if it is a 2 times coating which consists of the base coating film layer 32 and the top coating layer 33 as shown in FIG. 6, it will apply twice with the thickness of 20-25 micrometers, respectively.

  According to this embodiment, alumina ceramic fine powder 21 is the main component on the inner wall surface of the cooking chamber 11, the surface of the cooking utensil (square plate 13, grilled plate 14, grilled net 15), and the inner surface of the door 16. By forming a coating film 12 of an inorganic material that does not contain an organic compound, the surface hardness of these parts is increased to improve wear resistance, and the non-adhesiveness to dirt is increased to make it difficult to attach dirt. The attached dirt can be easily wiped off, and a cooking device excellent in cleanability can be realized.

  Although the microwave oven 1 has been described in the present embodiment, the coating film 12 made of an inorganic material that does not contain an organic compound mainly composed of alumina ceramic fine powder 21 is used for cooking in other cooking devices such as a microwave oven. It can also be formed on the inner wall surface of the room and the inner side surface of the door, and also on the inner wall surface of the grill part of the IH cooking heater, the inner side surface of the door, and the surface of a saucer or a grill net that is a cooking utensil in the grill. It can also be formed. Here, the main body forming the cooking chamber of the microwave oven or the grill portion of the IH cooking heater corresponds to a cooking chamber that accommodates the food to be cooked and heats it.

  When a cross-cut test was performed on the square plate 13 of the example coated with alumina ceramic powder (fine powder 21) having an average particle size of 10 nm, peeling of the coating film did not occur even with a 4H pencil. Further, a drop test of 0.1 ml and 0.2 ml water droplets was performed, but no water droplet spread was observed. On the other hand, about the square plate 13 which coated the silicone type paint of the comparative example, coating-film peeling was seen with the pencil of H hardness. Moreover, some spread of water droplets was observed.

  Eggs, sauces, ketchup, sugar, salad oil, soy sauce, vinegar, lemon, butter, sauteed grilled meat are hung on a square plate 13 and placed in the cooking chamber 11 of the microwave oven 1 at 300 ° C. for 30 minutes. After washing with a neutral detergent, a test of wiping with a towel was performed. As a result, the square dish 13 of the example coated with alumina ceramic powder could be wiped cleanly without any traces. On the other hand, in the case of the square plate 13 of the comparative example, the soy sauce and butter could be wiped cleanly, but a trace was left about the egg, sauce, sugar, salad oil, vinegar, lemon, and grilled meat. And in Ketchup, the trace was conspicuous.

  Thus, in the case of the square dish 13 of the present embodiment, it was confirmed that the surface hardness was strong, the dirt was hardly attached, the attached dirt was easily wiped off, and the cleaning property was excellent.

(2) 1st embodiment Next, 1st embodiment which actualized the said embodiment is described. In the following embodiments, descriptions overlapping with the above embodiments are omitted.

In FIG. 7, the base material 31 is made of a metal such as aluminum or iron, or a surface-treated steel plate such as aluminum plating or galvanization. And on the surface of the base material 31, the main component is fine powder 21 as an inorganic component of 1000 nm or less, preferably 100 nm or less of silicone (SiO) or alumina (AL ₂ O ₃ ), the film thickness is 5 to 35 μm, Preferably, a base coating layer 32 having a thickness of 10 to 25 μm is applied, and fine powder 21 as an inorganic component having a silicone or alumina particle size of 1000 nm or less, preferably 100 nm, is formed on the upper surface of the base coating layer 32. A ceramic layer having a film thickness of 8 to 65 μm, preferably 15 to 50 μm is formed by coating the top coating layer 33 having a film thickness of 3 to 30 μm, preferably 2 to 25 μm, as a main component. Is formed as a coating film 12 on the surface.

  In this case, by setting the film thickness of the base coating film layer 35 to 35 μm or less, preferably 25 μm or less, the heating in the baking process of the coating film 12 or the heating and cooling when actually used as the microwave oven 1 is possible. From the difference in thermal expansion between the metal that is the material 31 and the ceramic layer that is the coating film 12, the generation of fine cracks generated on the surface of the coating film 12 is suppressed.

  When the film thickness of the base coating film layer 32 is 35 μm or more, the crack width generated on the surface of the coating film 12 becomes large (3 μm or more), the dirt enters the crack, the burnt dirt bites, and the carbonized dirt becomes difficult to wipe off. . Also, when the crack width becomes wider (more than 5μm), and more cracks (more than 1 / 1mm square), the end of the crack is hung, cellophane tape is applied, and cellophane tape is peeled off rapidly In the tape peeling test, it was confirmed that the ceramic particles were peeled in a granular form. As a result of the experiment, the film thickness of the base coating film layer 32 was 35 μm or less, preferably 25 μm or less, resulting in less cracking. Further, when the base coating film layer 32 is too thin, the masking of the base material 31 is worsened and the base material 31 may be seen through. Therefore, in the experiment, 5 μm or more, preferably 10 μm is good in appearance. It became a result.

  In addition, in order to suppress the occurrence of cracks and to suppress the granular peeling phenomenon of ceramics in the tape peeling test, the film thickness of the top coating layer 33 is 30 μm or less, preferably 25 μm or less. It was an effective result. Moreover, if the film thickness of the top coating layer 33 is too thin, the concealing property of the base coating layer 32 is deteriorated, and if the base coating layer 32 is partially exposed on the surface, the surface of the coating film 12 is roughened. In addition to reducing the gloss, it also causes a decrease in water repellency. In the experiment, in the case of the fine powder 21 having a particle size of 1000 nm to 100 nm, the base coating layer 32 is well concealed by setting the average thickness of the top coating layer 33 to 3 μm or more, preferably 5 μm or more, As a result, the roughness of the surface of the coating film 12 can be suppressed.

  According to the above results, the total film thickness of the base coating film layer 32 and the top coating film layer 33 is 8 to 65 μm, preferably 15 to 50 μm, so that there are few cracks on the surface of the coating film 12 and There is no granular peeling, and a good appearance with no roughness or lack of gloss on the surface of the coating film 12 can be secured.

  Thereby, in addition to the microwave oven 1 shown in FIG. 1, a microwave oven having other oven functions, a microwave oven having a grill heating function, a cooking device such as a fish roaster, and the heating cooker are attached. In the cooking utensils (square plate 13, grilling plate 14, grilling net 15), both the heat resistance of ceramics and the non-adhesiveness (difficult to get dirty) of the fine nano-sized film, and the conventional silicone and fluorine Like coating, organic compound dissolves and decomposes during abnormal heating such as when equipment breaks down, and harmful gases are generated. It is non-adhesive at low temperatures, but softens at high temperatures. The disadvantage that non-adhesiveness deteriorates can be eliminated.

  In addition, since the ceramic film made of fine powder 21 is the main film, it has high hardness and is not easily scratched. Even when the surface of the coating film 12 is scorched by high-temperature heating of the microwave oven 1, the carbide is easily removed to prevent scratching. it can. Ceramics has high heat radiation efficiency, and heat radiation from the heater 8 provided on the outer surface of the cooking chamber 11 to the inner surface (bottom surface, left side surface, right side surface, back surface, top surface) of the cooking chamber 11 as an oven cabinet. The cooking performance as the microwave oven 1 is improved. Moreover, since the coating film 12 can ensure non-adhesiveness even at high temperatures, for example, kitchen paper can be placed on a cooking dish (corner plate 13 or grilled plate 14) for cooking, or oil can be placed on the cooking dish for cooking. There is no need to take care of cleaning up and so on, and you can cook healthy without using oil or reducing oil.

  The nano-ceramic coating film 12 is preferably applied to the surface of the cooking utensil housed in the cooking chamber 11 as well as the inner surface of the cooking chamber 11. Conventionally, the contact between both the cooking chamber 11 and the cooking utensil is likely to be soiled or the seasoning is burnt, and the burning is solidified in the gap and the cooking utensil sticks into the cooking chamber 11, and cooking is performed from the cooking chamber 11. Although it becomes difficult to take out the utensil, the cooking utensils can be easily attached and detached even when the seasoning or the like in the gap is burnt by high temperature heating by coating the both contact portions of the utensil.

  Thus, the non-adhesiveness can be obtained by forming the coating film 12 of ceramics having a fine particle size of nanometer level and high hardness mainly of the fine particles 21 made of alumina ceramics having a particle size of 1000 nm or less, preferably 100 nm or less. A water-repellent film is formed, and it is possible to provide a cooking chamber 11 and a cooking utensil that are less likely to be scratched and are less likely to adhere to dirt. Further, since the coating film 12 is mainly composed of ceramics and does not contain organic compounds such as silicone, fluorine, PES, and acryl, the organic compound softens and has a hardness even at a high temperature exceeding 230 ° C. as in the prior art. Even if the food to be cooked or seasoning adheres and burns by heating, the non-adhesiveness can easily wipe off the dirt, so the dirt is forcibly removed. The problem of scratching can also be solved.

  By the way, as a method of generating the ceramic coating film 12, the method of adding ceramic powder to an organic paint exposes the organic compound to the surface, and the above effect cannot be obtained. In the method of forming ceramics by spraying, the strength of the base material 31 is a problem, and the sheet metal forming the cooking chamber 11 does not have strength. In addition, it is difficult to form a nano-sized ceramic powder layer having good stain resistance and water repellency. Therefore, in each embodiment of the present invention, the sol-gel method is selected as a means for generating a ceramic thin film as the coating film 12.

  Specifically, the base material 31 is first heated to 60 ° C., then the base coating layer 32 is applied on the surface of the base material 31 and heated at 60 ° C. for 10 minutes to apply the top coating layer 33. . After coating the top coating layer 33, the temperature is raised to 120 ° C or 150 ° C for 3 minutes or more, preferably 5 minutes or more, and 120 to 250 ° C for 5 minutes or more, preferably 150 to 220 ° C for 15 minutes or more. The coating film 12 which becomes a ceramic layer is formed by heating and baking.

  In FIG. 7, the base coating layer 32 may be colored by adding a coloring pigment 36 of an inorganic component such as Cr, Mn, or Fe to the base coating layer 32. Since the presence or absence of coating on the surface of the base material 31 can be easily understood by the colored pigment 36, it is possible to improve the problem of forgetting to paint during the work of the base coating film layer 32 or partially reducing the film thickness. Similar coloring is conventionally known, but the heat resistance of the coating film 12 can be maintained by using the coloring pigment 36 of an inorganic component having particularly high heat resistance. In particular, in the present invention, the management of the film thickness is an important point for ensuring the performance, and it is an effective policy that can be visually recognized when the base coating layer 32 is coated when the film thickness is too thick or too thin. Become. In addition, the use of a black-colored color pigment 36 is preferable because the stain is less noticeable during long-term use.

  In FIG. 7, the color pigment 36 is added to the top coating layer 33 as well as the base coating layer 32. The coloring pigment 36 added to the top coating layer 33 may be less than that of the base coating layer 32, or the pigment may not be added to the top coating layer 33. By making the film layer 33 transparent, the interface between the base coating layer 32 and the top coating layer 33 can be easily observed. In particular, in the present invention, as described above, the management of the film thickness is an important point for ensuring the performance. Therefore, if the top coating layer 33 is made transparent, the thickness of the top coating layer 33 can be reduced when it is applied. If it is too thick or too thin, it can be visually recognized and is an effective measure. Furthermore, when the film thickness of the top coating layer 33 is thin, roughness occurs on the surface of the coating film 12. Conversely, if the film thickness of the top coating layer 33 is too thick, the transparency of the coating film 12 becomes strong. As a result, the film thickness of the top coating layer 33 and the total coating thickness of the coating layer 12 including the base coating layer 32 can be visually confirmed. Further, the surface of the coating film 12 becomes a transparent glossy surface, and there is an effect of improving the appearance quality.

  In FIG. 7, if a bright component pigment 37 such as mica particles or aluminum particles is added to the top coating layer 33, the top coating layer 33 glitters in a granular form, and the base coating layer 32 and the top coating layer 33 are further divided. The boundary surface can be observed more easily. Further, the coating film 12 has a metallic or pearly appearance, and the appearance quality is further improved.

  As described above, when the coating film 12 is formed, after the top coating layer 33 is applied, the temperature is increased to 120 ° C. or 150 ° C. for 3 minutes or more, preferably 5 minutes or more, and 120 to 250 ° C. And baked at 150 to 220 ° C. for 15 minutes or longer to form a coating film 12 to be a ceramic layer. The heating and baking temperature here is set lower than the maximum cooking temperature in the cooking chamber 11 during cooking, and the base coating layer 32, the top coating layer 33, or the base material 31, The thing whose heat-resistant use temperature of an ingredient is below the above-mentioned maximum heating temperature at the time of cooking is selected. In this way, when cooking in the microwave oven 1, the temperature is equal to or higher than the firing temperature for forming the coating film 12, and is equal to or lower than the heat resistant use temperature of the components of the base coating layer 32 and the top coating layer 33 or the components of the base material 31. The heating temperature can be the maximum temperature at which cooking is possible.

  At the time of baking the coating film 12, it plays a role of dehydrating moisture in the coating film 12 and activating molecular bonds. However, as a result of experiments, it has been found that the surface of the coating film 12 is cracked when the temperature is rapidly increased. It was. Generation of cracks can be suppressed by slowly raising the time required to reach the firing temperature (120 ° C. or 150 ° C.) over 3 minutes, preferably over 5 minutes.

  Further, the subsequent firing temperature is set to 120 to 250 ° C., preferably 150 to 220 ° C., because if the temperature is too low, the dehydrating action is poor, and if it is too high, it causes surface cracks. Furthermore, if the firing time is short, dehydration and molecular bonding will not proceed sufficiently, and by heating and firing for 5 minutes or more, preferably 15 minutes or more, the adhesion of the ceramic layer is improved, and granular peeling in the tape peeling test is performed. I was able to lose it.

  The coating film 12 completed by firing has the heat resistance of ceramics, withstands a temperature of 120 to 250 ° C. higher than the firing temperature during cooking, and the heat resistance temperature of the ceramics (coating film 12) or the base material 31 Withstands high temperatures of about 400 ° C (in the case of iron-based steel plates) up to the heat-resistant temperature. If the base material 31 is made of heat-resistant stainless steel or heat-resistant steel plate such as incoloy, the temperature can be raised to about 600 to 800 ° C. (up to the heat resistance temperature limit of either the ceramic or the base material). In addition to cooking dishes that can withstand the heating of the microwave oven 1 at, for example, 250 to 800 ° C., because of the main body, there is no generation of gas due to dissolution of organic compounds. Can be applied to the inner surface of the cooking chamber 11, the inner surface of the glass of the door 16 (base material is heat-resistant glass), the surface of the ceramic plate (example of the microwave oven 1) on the bottom surface of the cooking chamber 11, and cooking utensils for gas / electric stove is there.

  In the case of conventional organic compound paints, it is difficult to use at a temperature exceeding the firing temperature (fluorine decomposes and dissolves at about 400 ° C. and gas is generated), and the firing temperature must be increased. However, in the present invention, the firing temperature at the time of forming the coating film 12 can be lowered, and only the water contained in the paint as the liquid 22 evaporates at the time of firing. The above problem is eliminated. In addition, since it can be fired at a low temperature, the energy consumption of the firing furnace can be reduced.

  The above-mentioned coating film 12 shown in FIG. 7 is applied as a ceramic layer to the inner surface of the cooking chamber 11 which is a heating cooking chamber, or the surface of cooking utensils such as a square plate 13, a baking plate 14 and a grilling net 15 used during cooking. It is formed. Thereby, in addition to the microwave oven 1 shown in FIG. 1, cooking performance (no oil or weight loss, high temperature cooking) of other cooking devices such as a microwave oven and an oven, cleanability (dirt resistance, high hardness), It is possible to improve safety (no harmful gas generation, no organic compound), economy (reduction of firing furnace power), and the like.

  Thus, the heating cooker and cooking utensil according to the present embodiment have a fine powder 21 as an inorganic component having a silicone-based or alumina-based particle size of 1000 nm or less on the surface of the base material 31 made of metal or surface-treated steel. Mainly having a base coating layer 32 having a thickness of 5 to 35 μm and fine powder 21 as an inorganic component having a silicone or alumina particle size of 1000 nm or less, and having a thickness of 3 to 30 μm. The top coating layer 33 thus applied is applied in layers to form a ceramic layer having a thickness of 8 to 65 μm as the coating layer 12.

  In this case, by forming the ceramic coating film 12 mainly composed of the fine particles 21 having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material 31, and the scratches are high in hardness. It is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 that are less likely to be attached and that are less likely to adhere dirt. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 having high hardness and being hard to be scratched and having non-adhesiveness to which dirt is difficult to adhere, easy to wipe off dirt and excellent cleanability.

  Further, by making the thickness of the base coating film layer 32 35 μm or less and the thickness of the top coating layer 33 30 μm or less, the occurrence of fine cracks generated on the surface of the coating film 12 is suppressed, and the tape peeling The granular peeling phenomenon of ceramics in the test can be suppressed, and by making the thickness of the base coating film layer 32 to be 5 μm or more, the base material 31 can be concealed and a good appearance can be obtained. By setting the film thickness of the layer 33 to 3 μm or more, it is possible to suppress the roughness of the surface of the coating film 12 while concealing the base coating layer 32 and maintaining a good appearance.

  Further, in the present embodiment, the base coating layer 32 is colored by adding an inorganic component pigment 36. If it carries out like this, it will become easy to understand the presence or absence of the coating with respect to the base material 31 surface, and if a film thickness is too thick at the time of the coating of the base coating film layer 32, it can visually recognize. Moreover, the heat resistance of the coating film 12 can be maintained.

  In this embodiment, the amount of the color pigment 36 added to the top coating layer 33 is set to be smaller than the amount of the color pigment 36 added to the base coating layer 32, or the color pigment is added to the top coating layer 33 otherwise. The top coating layer 33 is formed transparently.

  In this case, by making the top coating layer 33 transparent, the interface between the base coating layer 32 and the top coating layer 33 can be easily observed, and the film thickness is too thick when the top coating layer 33 is applied. Or when it is too thin. Furthermore, when the film thickness of the top coating layer 33 is thin, roughness occurs on the surface of the coating film 12, and if the film thickness of the top coating layer 33 is too thick, the transparency of the coating film 12 becomes strong. Thus, the film thickness of the top coating film layer 33 and the film thickness of the coating film 12 including the base coating film layer 32 can be visually confirmed. Moreover, the surface of the coating film 12 becomes a transparent glossy surface, and the appearance quality is improved.

  In the present embodiment, the bright component pigment 37 is added to the top coating layer 33 to make the top coating layer 33 have a metallic or pearly appearance. Thereby, the top coating layer 33 glitters in a granular form, and the interface between the base coating layer 32 and the top coating layer 33 can be observed more easily. Further, the appearance quality of the coating film 12 is further improved.

  Moreover, in this embodiment, after the top coating layer 33 is applied, the temperature is increased to 120 ° C. or 150 ° C. over 3 minutes, and is heated and fired at 120 to 250 ° C. for 5 minutes or more to form the coating film 12 as a ceramic layer. And the heating temperature that is equal to or higher than the heat-baked temperature at the time of cooking and less than the heat-resistant use temperature of the component of the base coating layer 32 and the top coating layer 33 or the component of the base material 31. It is said.

  In this case, generation of cracks on the surface of the coating film 12 can be suppressed by increasing the temperature to 120 ° C. or 150 ° C. over 3 minutes after the top coating layer 33 is applied. Moreover, the adhesiveness of the coating film 12 improves by heating and baking at 120-250 degreeC for 5 minutes or more after that, and the granular peeling in a tape peeling test can be eliminated. The coating film 12 completed by firing can withstand temperatures higher than the firing temperature as long as it is below the heat-resistant use temperature of the components of the base coating layer 32 and the top coating layer 33, or the components of the base material 31, and is an organic compound. There is no generation of gas due to the dissolution of. In addition, since only moisture is evaporated during firing, no toxic gas is generated, and there is no problem in terms of safety, environment, and firing is possible at low temperatures, so that the energy consumption of the firing furnace can be reduced.

  Moreover, in this embodiment, in the microwave oven 1 as a heating cooker provided with the heating cooking chamber 2 and the cooking utensils (square plate 13, grilling plate 14, grilling net 15), the coating film 12 as the ceramic layer described above is applied. It forms in the inner surface part of the heating cooking chamber 2, or the surface part of a cooking utensil.

  By doing in this way, the effect by having formed the coating film 12 can be applied also to the inner surface part of the heating cooking chamber 2, or the surface part of a cooking utensil.

(3) Second Embodiment FIG. 8 shows a second embodiment of the present invention. The difference from the first embodiment is that a rough surface 41 having a surface roughness of 1.5 to 6.5 μm, preferably 3 to 5 μm, is formed on the surface of the base material 31. The rest is the same as in the first embodiment, and the above-mentioned base coating layer 32 and top coating layer 33 are applied on the surface of the rough surface 41, and the surface of the base material 31 has a film thickness of 8 The coating film 12 is formed as a ceramic layer of ˜65 μm, preferably 15˜50 μm. In addition to the inner wall surface of the cooking chamber 11 and the inner surface of the door 16 constituting the cooking chamber 2 shown in FIG. 1, the coating film 12 is applied to the surface of cooking utensils such as a square dish 13, a grill plate 14, and a grill net 15. It is formed.

  Before painting, it is possible to roughen the painted surface of the base material with sand blast, alumina blast, chemical etching, etc., and paint the rough surface to adhere the coating film by the anchor effect between the rough surface and the coating film It is known as a general processing method. However, in the case of the coating film 12 mainly composed of the fine powder 21 as an inorganic component of 1000 nm or less, preferably 100 nm or less as in the present invention, the surface roughness of the base material 31 to be coated is very important and is too fine. Even if it is too rough, the adhesiveness is lowered. In the experiment, a rough surface 41 having a surface roughness of the base material 31 of 1.5 to 6.5 μm, preferably 3 to 5 μm, is formed by blasting, and the base coating layer 32 and the top coating are formed on the rough surface 41. The coating layer 12 is formed with the film layer 33, and a tape peeling test (inspecting peeling of the coating film when the cellophane tape is applied and the cellophane tape is abruptly removed) or a cross-cut tape peeling test (with a cutter) A 1 mm square cell was cut into 100 mm and a cellophane tape was attached, and the cell coating was peeled off when the cellophane tape was rapidly removed. As a result, it was confirmed that there was no peeling of the coating film 12 in both tests.

  Further, the inside of the cooking chamber 2 serving as an oven chamber is composed of at least five elements of a ceiling surface, a left side surface, a right side surface, a bottom surface, and a back surface by a plate-shaped base material 31, which is not illustrated. However, the end portions of these plate-like elements form a box-like housing that is fixed to each other by a fastening member such as welding, caulking, or screwing.

  Here, when the inner surface of the cooking chamber 2 is blasted after being made into a housing, when performing the blasting process to the inner surface where the cooking chamber 2 is deep, the concavo-convex portion and the hole end portion formed in advance on the inner surface, and There is a problem that the surface of the joint surface between the elements is not sufficiently blasted and roughening is insufficient. Therefore, in this embodiment, the surface roughness as described above is 1.5 to 6. before the ends of the elements constituting the cooking chamber 2 are joined and fixed by welding, caulking, screwing, or the like. By performing blasting to form the rough surface 41 of 5 μm, preferably 3 to 5 μm, the effect of preventing partial roughening when the housing is blasted can be obtained.

  In addition, when the above-described elements are joined and fixed as the cooking chamber 2, the rough surface 41 formed on the surface of the base material 31 may be lost by an external force, and the surface of the base material 31 may be removed. There is a possibility that dirt may adhere to the film, and there is a risk that it becomes a cause of lowering adhesion after the coating film 12 is applied. So, in this embodiment, after fixing the edge part of each element which comprises the heating cooking chamber 2, before coating the coating film 12 on the surface of the base material 31, it blasts again and the inside of the heating cooking chamber 2 is carried out. By roughening each surface with an uneven rough surface 41 of 1.5 to 6.5 μm, preferably 3 to 5 μm, it becomes possible to avoid such a risk of reducing adhesion.

  As mentioned above, in this embodiment, in the microwave oven 1 as a heating cooker provided with the heating cooker 2 and the cooking utensils, the exposed surfaces of these cooking utensils 2 and cooking utensils are made of metal or surface-treated steel. A rough surface 41 having a surface roughness of 1.5 to 6.5 μm is formed on the surface of the base material 31, and an inorganic component having a silicon-based or alumina-based particle size of 1000 nm or less on the rough surface 41. Mainly the fine powder 21 as a base, the base coating layer 32 having a film thickness of 5 to 35 μm, and the fine powder 21 as an inorganic component having a silicone or alumina particle size of 1000 nm or less, A top coating layer having a thickness of 3 to 30 μm is applied in layers, and a ceramic layer having a thickness of 8 to 65 μm is formed as the coating layer 12.

  By doing in this way, in the heating cooking chamber 2 and cooking utensil of the microwave oven 1, the coating film 12 is not easily peeled off from the base material 31 while maintaining the effects of the first embodiment described above. The adhesion between the base material 31 and the coating film 12 can be improved.

  The cooking chamber 2 of the present embodiment is composed of five elements of a ceiling surface, a left side surface, a right side surface, a bottom surface, and a back surface by a base material 31, and the end portions of these elements are fixed. The uneven rough surface 41 is formed on the surface of the base material 31 before the elements are fixed.

  In this case, after fixing the end portions of each element to be the heating cooker 2, when trying to form the rough surface 41 on the inner surface, roughening may be insufficient, By forming the uneven rough surface 41 on the surface of the base material 31 before fixing, the lack of roughening can be solved.

  Moreover, in this embodiment, the uneven | corrugated rough surface 41 is again formed in the surface of the base material 31 before coating the coating film 12 after fixing each element used as the heating cooking chamber 2. As shown in FIG.

  Thus, after fixing each element which comprises the heating cooking chamber 2, before coating the coating film 12 on the surface of the preform | base_material 31, the surface is roughened by the rough surface 41 again, and coating is carried out. It is possible to avoid the risk of reducing the adhesion after the film 12 is applied.

(4) Third Embodiment Next, a third embodiment of the present invention will be described. As described in the second embodiment, the heating cooking chamber 2 serving as an oven chamber includes a plate-shaped base material 31 having at least five elements, that is, a ceiling surface, a left side surface, a right side surface, a bottom surface, and a back surface in the chamber. A case having an open front is configured by joining and fixing the end portions of each element by using fastening members such as welding, caulking, and screwing. Further, as shown in FIG. 1, a front frame 18 exposed as a front surface of the heating cooking chamber 2 when the door 16 is opened is provided on the outer periphery of the opening surface of the opened casing. Bonded and secured to the right and bottom elements.

  The same coating film 12 as that shown in each of the above embodiments is applied to the front frame 18 of the cooking chamber 2. As shown in FIG. 7 and FIG. 8, the coating film 12 as a ceramic layer mainly composed of fine powder 21 as an inorganic component of 1000 nm or less, preferably 100 nm or less of silicone or alumina on the surface of the base material 31. Is formed. 7 and 8 each show two coats 12 of the base coat layer 32 and the top coat layer 33. However, only one coat 12 of the top coat layer 33 is used as the mother coat. It may be formed on the surface of the material 31.

  By forming such a coating film 12 on the surface of the base material 31 of the front frame 18, it is possible to easily wipe off foreign matters such as dirt on the surface of the front frame 18. In addition, when the dirt is stuck by carbonization or the like due to heating of the microwave oven 1 (when fixed), even if the carbonized fixed object is scraped off with a scrubber or a spatula, the surface of the front frame 18 is not easily damaged. Since the dirt can be easily removed, the surface of the front frame 18 is hardly deformed. As a result, when the door 16 is closed and opposed to the front frame 18, the gap dimension between the door 16 and the front frame 18 can be stably maintained. ) It is suppressed that the gap is partially widened or narrowed. Therefore, when the gap becomes large, the hot air in the cooking chamber 2 leaks from the gap and the problem that the heating performance deteriorates can be solved. When the gap becomes narrow, the cooking chamber 2 The problem that the difference with the temperature in the actual heating cooking chamber 2 with respect to setting temperature becomes large, such as the heating temperature inside becomes high, can be solved.

  In addition to the oven function provided with the heater 8, in the case of the microwave oven 1 to which microwave heating by the microwave generator 9 is added, a gap partially expands during microwave heating from the microwave generator 9. In this case, it is possible to solve various problems that the radio wave leaks and the microwave heating characteristics change when the gap becomes narrow.

  In the present embodiment, the coating film 12 may be colored by adding a color pigment 36 of an inorganic component such as Cr, Mn, or Fe to the coating film 12. Since the presence or absence of coating on the surface of the base material 31 can be easily understood by the colored pigment 36, it is possible to improve the problem of forgetting to apply the coating film 12 or partially reducing the film thickness. Further, since the coloring pigment 36 has an inorganic and high hardness component, there is an effect that when the dirt is carbonized and fixed, it is less likely to be damaged when scraped off with a spatula or the like. In addition, if the black color pigment 36 is used, it is more preferable that the stain is not noticeable when used for a long period of time.

  Further, as shown in FIGS. 7 and 8, the coating film 12 is made into two coats of a base coating layer 32 and a top coating layer 33, and the color pigment 36 added to the top coating layer 33 is the base coating layer 32. Alternatively, the top coating layer 33 may be formed as a permeable membrane without adding any pigment to the top coating layer 33. Thus, the presence of the permeable membrane at the top of the coating film 12 improves the gloss (gloss) of the appearance of the front frame 18 and improves the appearance quality such as reducing the roughness of the front frame 18 surface. Further, when dirt is attached to the front frame 18, the color difference from the dirt becomes clear, the visibility of the dirt is improved, and usability during cleaning can be improved.

  Further, if a bright component pigment 37 such as mica particles or aluminum particles is added to the top coating layer 33, the top coating layer 33 glitters in a granular form, and the boundary surface between the base coating layer 32 and the top coating layer 33. Can be observed more easily. Further, the coating film 12 has a metallic or pearly appearance, and the appearance quality is further improved.

  As described above, in the present embodiment, in the cooking device provided with the cooking chamber 2, the cooking chamber 2 is composed of the five elements of the ceiling surface, the left side surface, the right side surface, the bottom surface, and the back surface by the base material 31. When the door 16 is opened around the outer periphery of the opening of the housing, the door 16 for opening and closing the opening of the housing is provided. A ceramic layer mainly comprising fine powder 21 as an inorganic component having a silicone-based or alumina-based particle size of 1000 nm or less is provided on the surface of the opening frame 18 as an opening frame 18 serving as a frame in front of the cooking chamber 2. Is formed as the coating film 12.

  In this case, non-adhesiveness and water repellency are provided on the surface of the base material 31 by forming the ceramic coating film 12 mainly composed of the fine particles 21 having a particle diameter of 1000 nm or less in the opening frame 18 of the cooking chamber 2. The opening frame 18 of the microwave oven 1 in which the film | membrane which has is formed, it is hard to be damaged with high hardness, and a dirt cannot adhere easily can be provided. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide the opening frame 18 of the microwave oven 1 that has high hardness, is hard to be scratched, has non-adhesiveness to which dirt is difficult to adhere, is easily wiped off, and has excellent cleanability.

  In addition, when foreign matters such as dirt are deposited on the surface of the front frame 18, it can be easily wiped off. Further, even if the carbonized fixed matter fixed by heating in the microwave oven 1 is scraped off with a scrubber or a spatula, the surface of the front frame 18 is less likely to be scratched and the surface of the front frame 18 can be easily removed. It becomes difficult to deform. Thereby, the clearance dimension of the door 16 and the front frame 18 can be maintained stably, and the problem that the difference with the temperature in the actual heating cooking chamber 2 with respect to the setting temperature as the microwave oven 1 becomes large can be solved. . Therefore, it is possible to provide the front frame 18 of the microwave oven 1 that has high hardness, is hard to be scratched, has non-adhesiveness, and is easy to wipe off dirt, and is excellent in cleanability. Further, the door 16 and the front frame 18 can be provided. The gap size can be maintained stably.

  Further, in this embodiment, the pigment 36 is added to the coating film 12 for coloring. In this way, since the presence / absence of coating on the surface of the front frame 18 can be easily understood, it is possible to improve the problem of forgetting to apply the coating film 12 or partially reducing the film thickness. In addition, since the color pigment 36 has an inorganic and high hardness component, when the dirt is carbonized and fixed, there is an effect that even if it is scraped off with a spatula or the like, it is difficult to be damaged.

  The coating film 12 of this embodiment is formed by the base coating layer 32 and the top coating layer 33, and the amount of the coloring pigment 36 added to the top coating layer 33 is set to the amount of the coloring pigment 36 of the base coating layer 32. The amount is less than the addition amount, or else the color pigment is not added to the top coating layer 33, and the top coating layer 33 is formed as a permeable membrane.

  Thus, the appearance quality of the front frame 18 can be improved by forming a permeable film on the top of the coating film 12. Further, when dirt is attached to the front frame 18, the color difference from the dirt becomes clear, and the usability during cleaning can be improved.

  Further, in the present embodiment, the bright component pigment 37 is added to the top coating layer 33 to make the top coating layer 33 have a metallic or pearly appearance. As a result, the top coating layer 33 glitters in a granular manner in the opening frame 18, and the interface between the base coating layer 32 and the top coating layer 33 can be more easily observed. Further, the appearance quality of the coating film 12 is further improved.

(5) Fourth Embodiment Next, a fourth embodiment of the present invention will be described. In this case, the cooking chamber 2 serving as an oven chamber is composed of a plate-shaped base material 31 composed of at least five elements, ie, a ceiling surface, a left side surface, a right side surface, a bottom surface, and an inner back surface, and end portions of the respective elements. Are joined and fixed using a fastening member such as welding, caulking, or screwing to form a housing having an open front. Further, the top surface, the left side surface, the right side surface, the bottom surface, and the back surface forming the inside of the housing are mainly composed of fine powder 21 as an inorganic component having a silicone or alumina particle size of 1000 nm or less. Thus, a coating film 12 to be a ceramic layer is formed.

  When the film thickness of the coating film 12 is increased, cracks are likely to occur in the coating film 12 due to a difference in thermal expansion between the base material 31 and the coating film 12. On the other hand, when the film thickness of the coating film 12 becomes thin, the concealing property of the base material 31 by the coating film 12 decreases, and the base material 31 is seen through. Therefore, in this embodiment, such a problem is avoided by setting the film thickness of the coating film 12 to 8 to 65 μm, preferably 15 to 50 μm, but the inner surface (opposite surface of the opening surface) in the cooking chamber 2. ) Is difficult for light to enter, and even if the concealability of the base material 31 is lowered, there is no problem in appearance, so that the film thickness is made thinner than the other ceiling, left, right, and bottom surfaces. It becomes possible to reduce the amount of use.

  In addition, on the inner surface of the cooking chamber 2, a hole for supplying heat from the inner surface to the cooking chamber 11 of the cooking chamber 2 and an unevenness for fixing the heater 8 and a motor for blowing air are fixed. There may be. Referring to FIG. 1, reference numeral 19 corresponds to such an uneven portion. The end face of the hole and the concavo-convex portion 19 are easily affected by expansion and contraction due to heat during heating of the microwave oven 1, and are in an environment where cracks are likely to occur in the coating film 12. Connected. Therefore, in this embodiment, the coating film 12 formed on the surface of the base material 31 on the inner surface of the cooking chamber 2 including the holes and the concavo-convex portions 19 is made thinner than the other surfaces, thereby applying the coating. An effect of making it difficult for cracks to occur in the film 12 can be obtained.

  In the case of the microwave oven 1, the inner surface of the cooking chamber 2 is particularly difficult to see from the outside, but it is not limited to the inner surface, and is not limited to the inner surface. Accordingly, the coating film 12 may be formed to have a thinner film thickness than other portions at any location on the inner surface.

  As described above, in the present embodiment, in the cooking device provided with the cooking chamber 2, the cooking chamber 2 is composed of the five elements of the ceiling surface, the left side surface, the right side surface, the bottom surface, and the back surface by the base material 31. A casing having an opening formed by adhering the end portions of these elements is formed, and a fine powder 21 as an inorganic component having a silicone or alumina particle diameter of 1000 nm or less is formed on the inner surface of the casing. Mainly, a ceramic layer having a film thickness of 8 to 65 μm is formed as the coating film 12, and the coating film 12 formed on the back surface of the casing is thinner than the coating film 12 formed on the other surface of the casing. It is formed with a thickness.

  In this case, non-adhesiveness is formed on the surface of the base material 31 by forming the ceramic coating film 12 mainly composed of the fine particles 21 having a particle diameter of 1000 nm or less on the inner surface of the casing forming the cooking chamber 2. A casing of the microwave oven 1 in which a film having water repellency is formed, has high hardness, is hardly scratched, and is difficult to be attached with dirt. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide a housing of the microwave oven 1 that has high hardness, is hardly scratched, has non-adhesive properties that are difficult to adhere to dirt, is easy to wipe off dirt, and has excellent cleanability.

  In addition, by setting the film thickness of the coating film 12 to 8 to 65 μm, it is difficult for the coating film 12 to be cracked, and the base material 31 does not show through. However, since the inner surface of the cooking chamber 2 does not hinder the appearance even if the concealability of the base material 31 is reduced, the coating film 12 is formed with a thinner film thickness than the other surfaces. This makes it possible to reduce the amount of paint used.

  Moreover, in this embodiment, the back surface of the housing | casing which comprises the heating cooking chamber 2 is provided with the hole, the unevenness | corrugation (uneven part 19), or the hole and the unevenness | corrugation.

  The end face of the hole and the uneven portion 19 are in an environment in which cracks are likely to occur in the coating film 12, but the coating formed on the surface of the base material 31 on the inner surface of the cooking chamber 2 including the hole and the uneven portion 19. By making the film thickness of the film 12 thinner than that of the other surface, it is possible to obtain an effect that the coating film 12 is less likely to be cracked.

(6) Fifth Embodiment Next, a fifth embodiment of the present invention will be described. As shown in FIG. 9, in this embodiment, two coats of the coating film 12 including the base coating layer 32 and the top coating layer 33 shown in the first embodiment are formed in one coat. The coating film 12 is formed on the surface of the base material 31 as a ceramic layer having a lower limit of 8 μm or more, preferably a lower limit of 15 μm or more and an upper limit of 65 μm or less, preferably an upper limit of 50 μm or less. Also in this case, the surface cracks of the coating film 12 are reduced, granular peeling in the tape peeling test is prevented, and the appearance is neither metallic nor pearl, but the basic functions such as cleanability of the cooking chamber 2 and cooking utensils are improved. Can be achieved.

  Alternatively, the entire coating film 12 may be colored by adding a color pigment 36 of an inorganic component such as Cr, Mn, or Fe to the coating film 12. Since the presence or absence of coating on the surface of the base material 31 can be easily understood by the colored pigment 36, it is possible to improve the problem of forgetting to apply the coating film 12 or partially reducing the film thickness. Similar coloring is conventionally known, but the heat resistance of the coating film 12 can be maintained by using the coloring pigment 36 of an inorganic component having particularly high heat resistance. In particular, in the present invention, the management of the film thickness is an important point for ensuring the performance, and it is an effective measure that can be visually recognized when the film thickness is too thick or too thin when the coating film 12 is applied. In addition, the use of a black-colored color pigment 36 is preferable because the stain is less noticeable during long-term use. Other configurations are the same as those in the first embodiment, but the uneven rough surface 41 as in the second embodiment may be formed on the surface of the base material 31.

  Thus, in the present embodiment, the surface of the base material 31 made of metal or surface-treated steel is mainly composed of the fine powder 21 as an inorganic component having a silicone or alumina particle size of 1000 nm or less, and has a film thickness of 8 A ceramic layer of ˜65 μm is formed as the coating film 12.

  Also in this case, by forming the ceramic coating film 12 mainly composed of the fine particles 21 having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material 31, and the hardness is high. It is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 that are less likely to be scratched and less likely to be contaminated. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 having high hardness and being hard to be scratched and having non-adhesiveness to which dirt is difficult to adhere, easy to wipe off dirt and excellent cleanability.

  Further, in this embodiment, the pigment 36 is added to the coating film 12 for coloring. If it carries out like this, it will become easy to understand the presence or absence of the coating with respect to the base material 31 surface, and it can visually recognize when the film thickness is too thick at the time of coating of the coating film 12, or is too thin. Moreover, the heat resistance of the coating film 12 can be maintained.

  As a modification of the present embodiment, a two-coat coating film 12 including a base coating layer 32 and a top coating layer 33 as shown in FIG. 7 may be formed. In that case, a color pigment 36 of an inorganic component such as Cr, Mn, or Fe is added to the base coating layer 32 to color the entire base coating layer 32, and the coloring pigment 36 is also added to the top coating layer 33. . The amount may be less than that of the base coating layer 32 or the pigment may not be added to the top coating layer 33. However, the top coating layer 33 may be a transparent or transparent film as in the above embodiment. do not have to.

  Thus, in the present embodiment, the surface of the base material 31 made of a metal such as aluminum or iron, or surface-treated steel such as aluminum plating or galvanization, has a silicone or alumina particle size of 1000 nm or less, preferably 100 nm. Mainly fine powder 21 as the following inorganic component is added and colored by adding an inorganic component coloring pigment 36, and the film thickness is 5 μm or less, preferably 10 μm or less, preferably 35 μm or less, preferably 25 μm or less. Less coloring pigment 36 is added to base coating layer 32 and fine powder 21 mainly composed of an inorganic component having a silicone or alumina particle size of 1000 nm or less, preferably 100 nm or less. Alternatively, the color pigment 36 is not added, and the film thickness is 3 μm or more, preferably 5 μm or more, and the upper limit is 30 μm. The top coating layer 33 having an upper limit of m or less, preferably an upper limit of 25 μm or less, is applied in layers, so that the total of the base coating film 32 and the top coating film 33 is 8 to 65 μm, preferably 15 to The coating film 12 is formed as a ceramic layer having a film thickness of 50 μm.

  In this case, by forming the ceramic coating film 12 mainly composed of the fine particles 21 having a particle size of 1000 nm or less, a film having non-adhesiveness and water repellency is formed on the surface of the base material 31, and the scratches are high in hardness. It is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 that are less likely to be attached and that are less likely to adhere dirt. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide the cooking chamber 11 and the cooking utensil of the microwave oven 1 having high hardness and being hard to be scratched and having non-adhesiveness to which dirt is difficult to adhere, easy to wipe off dirt and excellent cleanability.

  Further, by making the thickness of the base coating film layer 32 35 μm or less and the thickness of the top coating layer 33 30 μm or less, the occurrence of fine cracks generated on the surface of the coating film 12 is suppressed, and the tape peeling The granular peeling phenomenon of ceramics in the test can be suppressed, and by making the thickness of the base coating film layer 32 to be 5 μm or more, the base material 31 can be concealed and a good appearance can be obtained. By setting the film thickness of the layer 33 to 3 μm or more, it is possible to suppress the roughness of the surface of the coating film 12 while concealing the base coating layer 32 and maintaining a good appearance.

  Further, the base coating layer 32 is colored by adding an inorganic component pigment 36. If it carries out like this, it will become easy to understand the presence or absence of the coating with respect to the base material 31 surface, and if a film thickness is too thick at the time of the coating of the base coating film layer 32, it can visually recognize. Moreover, the heat resistance of the coating film 12 can be maintained.

  Further, the addition amount of the color pigment 36 in the top coating layer 33 is made smaller than the addition amount of the coloring pigment 36 in the base coating layer 32, or else the coloring pigment is not added to the top coating layer 33. Thus, the boundary surface between the base coating layer 32 and the top coating layer 33 can be easily observed to some extent, and can be visually recognized when the film thickness is too thick or too thin when the top coating layer 33 is applied. .

  Moreover, even if the coating film 12 is either 1 coat or 2 coat mentioned above, when forming the coating film 12, after applying the top coating layer 33, it is 3 minutes or more to 120 degreeC or 150 degreeC, Preferably, the temperature is raised over 5 minutes or more, and then heated and fired at 120 to 250 ° C. for 5 minutes or more, preferably 150 to 220 ° C. for 15 minutes or more to form the coating film 12 to be a ceramic layer. The heating and baking temperature here is set lower than the maximum cooking temperature in the cooking chamber 11 during cooking, and the base coating layer 32, the top coating layer 33, or the base material 31, The thing whose heat-resistant use temperature of an ingredient is below the above-mentioned maximum heating temperature at the time of cooking is selected. In this way, when cooking in the microwave oven 1, the temperature is equal to or higher than the firing temperature for forming the coating film 12, and is equal to or lower than the heat resistant use temperature of the components of the base coating layer 32 and the top coating layer 33 or the components of the base material 31. The heating temperature can be the maximum temperature at which cooking is possible.

  At the time of baking the coating film 12, it plays a role of dehydrating moisture in the coating film 12 and activating molecular bonds. However, as a result of experiments, it has been found that the surface of the coating film 12 is cracked when the temperature is rapidly increased. It was. Generation of cracks can be suppressed by slowly raising the time required to reach the firing temperature (120 ° C. or 150 ° C.) over 3 minutes, preferably over 5 minutes.

  Further, the subsequent firing temperature is set to 120 to 250 ° C., preferably 150 to 220 ° C., because if the temperature is too low, the dehydrating action is poor, and if it is too high, it causes surface cracks. Furthermore, if the firing time is short, dehydration and molecular bonding will not proceed sufficiently, and by heating and firing for 5 minutes or more, preferably 15 minutes or more, the adhesion of the ceramic layer is improved, and granular peeling in the tape peeling test is performed. I was able to lose it.

  The coating film 12 completed by firing has the heat resistance of ceramics, withstands a temperature of 120 to 250 ° C. higher than the firing temperature during cooking, and the heat resistance temperature of the ceramics (coating film 12) or the base material 31 Withstands high temperatures of about 400 ° C (in the case of iron-based steel plates) up to the heat-resistant temperature. If the base material 31 is made of heat-resistant stainless steel or heat-resistant steel plate such as incoloy, the temperature can be raised to about 600 to 800 ° C. (up to the heat resistance temperature limit of either the ceramic or the base material). In addition to cooking dishes that can withstand the heating of the microwave oven 1 at, for example, 250 to 800 ° C., because of the main body, there is no generation of gas due to dissolution of organic compounds. Can be applied to the inner surface of the cooking chamber 11, the inner surface of the glass of the door 16 (base material is heat-resistant glass), the surface of the ceramic plate (example of the microwave oven 1) on the bottom surface of the cooking chamber 11, and cooking utensils for gas / electric stove is there.

  In the case of conventional organic compound paints, it is difficult to use at a temperature exceeding the firing temperature (fluorine decomposes and dissolves at about 400 ° C. and gas is generated), and the firing temperature must be increased. However, in the present invention, the firing temperature at the time of forming the coating film 12 can be lowered, and only the water contained in the paint as the liquid 22 evaporates at the time of firing. The above problem is eliminated. In addition, since it can be fired at a low temperature, the energy consumption of the firing furnace can be reduced.

  In the case where the main component of the coating film 12 is silicone-based and alumina-based inorganic component is 90% or more, preferably 95% or more, and the base coating layer 32 and the top coating layer 33 form two coats, the top coating Since the coloring pigment 36 contained in the film layer 33 has selected an inorganic component, there is almost no gas generation | occurrence | production from the coating film 12 at the time of actual use, and it can be used safely. In addition, even if the microwave oven 1 breaks down and becomes abnormally heated, or when cooking utensils are used in a gas or electric stove and are heated beyond the operating temperature limit, There is almost no gas generation and safety is improved.

  Furthermore, as a feature of ceramics, there is no red heat at high temperature, infrared radiation and absorption efficiency is high, and when used as a cooking utensil in a cooking plate or container, heat absorption is improved at high temperature. Moreover, when it uses for the inner surface of the cooking chamber 2, the thermal radiation efficiency into the cooking chamber 2 from the heater 8 provided in the outer surface of the microwave oven 1 improves, and heating efficiency improves. If applied to both the inner surface of the cooking chamber 2 and the cooking dishes and containers used in the cooking chamber 2, by the synergistic effect of improving the heat radiation from the heater 8 and improving the heat absorption of the cooking dishes and containers, It becomes possible to improve cooking performance.

  As described above, in the present embodiment, after the top coating layer 33 is coated, the coating film 12 is formed by heating and baking at a temperature lower than the temperature during cooking, and the heating and baking is performed when the coating film 12 is formed during cooking. The heating temperature that is equal to or higher than the above temperature and equal to or lower than the heat resistant use temperature of the component of the coating film 12 or the component of the base material 31 is set as the maximum usable temperature.

  In this case, the coating film 12 completed by firing can withstand a temperature higher than the firing temperature as long as it is equal to or lower than the heat-resistant use temperature of the component of the coating film 12 or the component of the base material 31, and There is no occurrence. In addition, since only moisture is evaporated during firing, no toxic gas is generated, and there is no problem in terms of safety, environment, and firing is possible at low temperatures, so that the energy consumption of the firing furnace can be reduced.

  In the present embodiment, the maximum usable temperature is preferably 230 ° C. or more and 400 ° C. or less. In this way, even the base material 31 using the iron-based steel material is not used beyond the heat resistance temperature of the base material 31, and the coating film 12 is mainly made of ceramics. Does not occur.

  Moreover, in this embodiment, the coating film 12 as a ceramic layer has an inorganic component of 90% or more. In this case, not only during actual use but also when the heating exceeds the maximum usable temperature, there is almost no gas generation as in the decomposition of the organic compound, and the safety is improved.

  In the present embodiment, for example, the rough rough surface 41 as described in the second embodiment may be formed on the surface of the base material 31.

(7) Sixth Embodiment Next, a sixth embodiment of the present invention will be described. Conventional coatings made of organic compounds such as fluorine and silicone or ceramic coatings made by adding ceramic particles to organic compounds have an initial pencil hardness of 2H to 4H. There was a problem that the organic compound was softened with the increase, and as a result, the pencil hardness as a coating film was lowered.

  Especially in non-adhesive and glossy coated films, organic compounds with high heat resistance cannot be used, and there is a drawback that the coated film softens at 230 ° C or higher, for example when heated at a high temperature of 300 ° C or higher. , Oil from cooking, soy sauce, ketchup and other seasonings are scorched and the coating is soft, so that the scorching is firmly attached to the coating and when it cools after cooking, it can be easily burnt There was a defect that could not be removed. In addition, when the scorch is scraped off with a spatula or the like, the coating film is damaged, and when it is used again, there is a problem that dirt is more likely to be stuck due to unevenness due to the scratch.

  In order to cope with such a problem, in this embodiment, in addition to the features of the embodiments corresponding to FIGS. 7 to 9, the pencil hardness of the surface particularly during non-cooking is 4H or higher, preferably 6H or higher. The heat receiving temperature of the coating film 12 at the time of cooking in the range 1 is 230 ° C. or higher, preferably 250 ° C. or higher, and the decrease in pencil hardness of the surface during heating is within 1 H, preferably the pencil hardness of the non-cooked surface. A ceramic layer in which an alumina ceramic particle (fine powder 21) having no decrease and having a silicone or alumina particle size of 1000 nm or less, preferably 100 nm or less is selected is formed on the surface of the base material 31 as the coating film 12. Further, the coating film 12 is configured so that the silicone-based or alumina-based inorganic component is 90% or more, preferably 95% or more. As a result, the pencil hardness of the surface of the coating film 12 is 6H or more in the initial stage of non-cooking (9H in the experiment), and since the main component is ceramics, even at temperatures of 230 ° C., 250 ° C., 300 ° C., 350 ° C. As a result of the experiment, the pencil hardness on the surface of the coating film 12 hardly decreases. When the base material 31 is iron or an aluminum-plated steel plate, the non-adhesion of the coating film 12 is maintained up to the heat resistant temperature limit of 400 ° C. The pencil hardness that can withstand the practical use was secured. By selecting Incoloy, Inconel, heat-resistant stainless steel, etc. with higher heat resistance as the base material 31, it is possible to withstand a practical heat-resistant temperature of 600 ° C. to 800 ° C. without reducing the hardness of the coating film 12 surface. It becomes.

  As a result, even if the food is placed on a cooking utensil (square plate 13, grill plate 14, grill net 15), put into the cooking chamber 11, and cooked at a high temperature of 230 ° C. or higher, When soy sauce, ketchup or the like burns onto the surface of the coating film 12, the burn can be easily removed.

  Further, conventionally, when baking cookies at about 170 ° C., there was a difficulty that the baked cookies stuck to the coating film due to the softening of the organic compound contained in the coating film, but the cooking utensil of the present invention was used. In the case, it did not stick to the coating film 12. In addition, when the chicken was grilled or grilled with the sword fish using a cooking utensil at a temperature of 350 ° C., there was no phenomenon that the skin of the cooked food stuck to the cooking utensil. Furthermore, when soy sauce, sauce, and ketchup were heated at 350 ° C. and burned onto the coating film 12 on the surface of the cooking utensil, the burn could be easily removed by simply wiping and cooling. In addition, even when a spatula is used, the pencil hardness of the surface of the coating film 12 in this embodiment is 6 H or more, which is twice or more compared with 2H to 3H of a normal organic compound paint. There were no scratches and there was no degradation in performance even after repeated use.

  As described above, the cooking utensil of the present embodiment has a coating film as a ceramic layer mainly composed of silicone-based or alumina-based ceramic particles (fine powder 21) on the surface of the base material 31 made of metal or surface-treated steel. 12, the coating film 12 has a surface pencil hardness of 4H or higher when not cooking, a heat receiving temperature of 230 ° C. or higher during cooking, and a decrease in pencil hardness of the surface being heated is within 1H. The ceramic component (fine powder 21) is selected.

  In this case, by forming the ceramic coating film 12 mainly composed of the fine particles 21, a film having non-adhesiveness and water repellency is formed on the surface of the base material 31. A cooking utensil that is difficult to adhere can be provided. In addition, since the coating film 12 does not contain an organic compound, the hardness and non-adhesiveness do not decrease even at high temperatures, and the non-adhesive property can easily wipe off dirt. The problem of removing dirt and scratching is also eliminated. Therefore, it is possible to provide a cooking utensil that has high hardness and is hard to be scratched and has non-adhesiveness to which dirt is difficult to adhere, and that is easy to wipe off dirt and has excellent cleanability.

  Moreover, even if the heat receiving temperature of the coating film 12 reaches 230 ° C. or higher, it is possible to withstand the practical heat resistance temperature as a cooking utensil without reducing the hardness of the coating film 12 surface.

  In addition, this invention is not limited to each embodiment mentioned above, A various change is possible in the range which does not deviate from the meaning of this invention. For example, as long as the composition of the coating film 12 is mainly composed of alumina ceramic powder, a small amount of other ceramic powder may be mixed. Further, as the cooking utensil, for example, a cooking container having a deeper dish shape than the illustrated square dish 13 or baking plate 14 may be used, and the above-described coating film 12 may be formed on the cooking container. In addition, you may combine the characteristic of each said embodiment suitably.

1 Microwave oven (heating cooker)
12 Coating film (ceramic layer)
21 Fine powder (inorganic component)
16 Door 18 Front frame (frame)
31 Base material 32 Base coating layer 33 Top coating layer 36 Color pigment (inorganic component pigment)
37 Bright component pigment (Bright component)
41 Rough surface

Claims (10)

On the surface of the base material made of metal or surface-treated steel,
A base coating layer having a film thickness of 5 to 35 μm mainly composed of an inorganic component having a silicone or alumina particle size of 1000 nm or less;
Applying the top coating layer with a film thickness of 3 to 30 μm as the main component, with the inorganic component as the main component,
After coating the top coating layer, the temperature is increased to 120 ° C. or 150 ° C. over 3 minutes, and heated and fired at 120 to 250 ° C. for 5 minutes or more to form a ceramic layer having a thickness of 8 to 65 μm.
A method for producing a cooking utensil , wherein a heating temperature equal to or higher than the heat-baked temperature and lower than a heat-resistant use temperature of a component of the ceramic layer or a component of the base material is set as a maximum cooking temperature during cooking. The method for producing a cooking utensil according to claim 1, wherein the base coating layer is colored by adding an inorganic component pigment. 3. The cooking utensil according to claim 1, wherein a pigment is added to the top coating layer less than the base coating layer or a pigment is not added, and the top coating layer is transparent . Manufacturing method . The method for producing a cooking utensil according to any one of claims 1 to 3, wherein a bright component is added to the top coating layer to make the top coating layer have a metallic or pearly appearance. . In a cooking device equipped with a cooking chamber and cooking utensils,
The cooking chamber and the cooking utensil are:
A rough surface with a surface roughness of 1.5 to 6.5 μm is formed on the surface of the base material made of metal or surface-treated steel,
The method for manufacturing a heating cooker, wherein the ceramic layer according to any one of claims 1 to 4 is formed on the rough surface. The cooking chamber is composed of five elements of the ceiling surface, left side surface, right side surface, bottom surface, and back surface by the base material, forming a housing that is open by fixing the end of each element,
With a door that opens and closes the opening of this housing,
Around the outer periphery of the opening of the housing, provided with a frame that becomes the front when the door is opened,
The method for manufacturing a heating cooker according to claim 5, wherein the ceramic layer according to any one of claims 1 to 4 is formed on a surface of the frame. In a cooking device equipped with a cooking chamber,
The cooking chamber is composed of five elements, a ceiling surface, a left side, a right side, a bottom, and a back surface, based on a base material, and has a housing that is open by fixing the end of each element,
On the inner surface of the housing, a ceramic layer having a film thickness of 8 to 65 μm is mainly formed of an inorganic component having a silicone or alumina particle size of 1000 nm or less,
The cooking device according to claim 1, wherein the ceramic layer formed on the inner surface of the housing is thinner than the ceramic layer formed on the other surface of the housing.   The cooking device according to claim 7, wherein holes and / or irregularities are provided in the inner surface of the casing. On the surface of the base material made of metal or surface-treated steel,
A base coating layer having a film thickness of 5 to 35 μm, mainly formed of an inorganic component having a silicone or alumina particle size of 1000 nm or less, colored by adding an inorganic component pigment,
Applying the top coating layer with a film thickness of 3 to 30 μm, with the inorganic component as the main component, with less pigment addition than the base coating layer or without adding pigment,
After the application of the top coating layer, a ceramic layer having a film thickness of 8 to 65 μm is formed by heating and firing at a temperature lower than the temperature during cooking.
At the time of the cooking, a heating temperature that is equal to or higher than the heat-baked temperature and is equal to or lower than the heat-resistant use temperature of the component of the ceramic layer or the component of the base material,
In the ceramic layer, the inorganic component is 90% or more, the pencil hardness of the surface during non-cooking is 4H or more, the heat receiving temperature during cooking is 230 ° C. or more, and the pencil hardness of the surface being heated is reduced. Is less than 1H , The manufacturing method of the cooking utensil characterized by the above-mentioned. 10. The method of manufacturing a cooking utensil according to claim 9, wherein the maximum usable temperature is 230 ° C. or higher and 400 ° C. or lower.

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