JP2003204871A - Container for electromagnetic cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container (typically, a dish) for an electromagnetic cooker with a heating layer with improved output while maintaining the durability, and a paste for forming the heating layer. <P>SOLUTION: The dish for the electromagnetic cooker comprises a dish body 10 made of a non-metal material (alumina or the like), the heating layer 20 disposed on the bottom of the dish body 10, and a protection layer 30 for covering the heating layer 20. The heat layer 20 is made of sintered metal powders mainly of conductive metal, and the sintered metal powders are substantially made of coated particles which are fine particles of conductive metal (Ag or the like) whose surface is coated with oxide ceramics. Alumina and/or zirconia is preferable as the oxide ceramics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-metal container such as tableware provided with a layer that generates heat by electromagnetic induction, and a structure of the heat generating layer.

[0002]

2. Description of the Related Art As a container for an electromagnetic cooker, a layer which heats by electromagnetic induction is provided on the bottom of a cooking container (cooking utensils such as pots and pans) or dishes mainly made of non-metallic materials such as ceramics and heat-resistant glass Things are known. The heat generating layer formed by firing a mixture of a metal powder mainly composed of a conductive metal and an inorganic binder is excellent in terms of easiness of manufacture and durability.

[0003]

By the way, if the output per unit area of the heat generating layer can be improved, the contents of the container can be rapidly heated, which is preferable. In particular, in the case of tableware with a smaller diameter than cooking utensils such as frying pans (especially Japanese dishes such as bowls, bowls, pots and hot water, various cups, sake bottles, etc.), a heating layer is formed. Since the area of the part suitable for the device is generally small, there is a great demand for such high output. One way to increase the output of the heat generating layer is to increase the thickness of the heat generating layer. However, when the thickness of the heat generating layer having the conventional composition is increased, there is a problem in forming the heat generating layer, and the durability may tend to decrease. In particular, in an electromagnetic cooker container having a structure in which the heat generating layer is covered with a protective layer such as a glass coat layer, if the thickness of the heat generating layer is increased, the glass coat layer may easily be penetrated (cracked).

Therefore, an object of the present invention is to provide a tableware or other container for an electromagnetic cooker provided with a heating layer capable of realizing a high output while suppressing the occurrence of the above phenomenon. Another object of the present invention is to provide a heating layer forming paste suitable for use in forming such a heating layer.

[0005]

Means, Actions and Effects for Solving the Problems The present inventor has found that the above problems can be solved by including a specific metal oxide in the heat generating layer.

The container for an electromagnetic cooker according to the present invention comprises a container body made of a non-metallic material and a heat generating layer provided at the bottom of the container body. The heat generating layer is formed by sintering a metal powder mainly composed of a conductive metal. The sintered metal powder is essentially composed of coated particles in which oxide ceramics are coated on the surface of fine particles made of a conductive metal.

According to such a heating layer, at least one of the following effects (1) and (2) can be obtained. (1). The durability can be excellent even when the thickness of the heat generating layer is relatively large. For example, as compared with a heating layer or the like in which metal powder consisting of fine particles not coated with oxide ceramics is sintered, the phenomenon that the heating layer floats or peels off from the container body is less likely to occur. Therefore, the thickness of the heat generating layer can be increased. (2). In a container for an electromagnetic cooker having a structure in which the heat generating layer is covered with a protective layer (such as a glass coat layer), even if the thickness of the heat generating layer is relatively large, penetration into the protective layer is unlikely to occur. Therefore, the thickness of the heat generating layer can be increased. Due to at least one of these effects, the container for an electromagnetic cooker of the present invention may include a heat generating layer having an improved output per unit area.

Examples of oxide ceramics include A
Oxide ceramics having any one element selected from the group consisting of 1, Zr, Ti, Y, Ca, Mg and Zn as a constituent element can be used. Preferred oxide ceramics are alumina and / or zirconia. The content of the oxide ceramics in the heat generating layer is approximately 0.005 to 10% of the mass of the conductive metal.
It is preferable that the amount is equivalent to. Further, as the conductive metal forming the heat generating layer, Ag or an alloy mainly containing Ag is preferably used from the viewpoints of cost and low electric resistance.

The average thickness of the heat generating layer is approximately 15-100.
It can be in the μm range. The heat generating layer provided in the container of the present invention is obtained by sintering a metal powder substantially composed of the coating particles. Therefore,
The surface of the fine particles (made of Ag or the like) forming the heat generating layer is coated with oxide ceramics. As a result, the heat-generating layer of the present invention exhibits excellent durability even in the configuration in which the protective layer (glass coating layer or the like) covering the heat-generating layer is not provided. For example, it is possible to suppress alteration of the conductive metal forming the heat generating layer (chemical change such as oxidation and sulfide, change in color tone) over a long period of time.
In the container for an electromagnetic cooker having no protective layer as described above, the preferable average thickness of the heat generating layer is about 15 to 10.
It is in the range of 0 μm, and a more preferable average thickness is about 20.
˜50 μm. Alternatively, the thickness of the heat generating layer can be 30 μm or more (typically 30 to 50 μm).

Further, the tableware for an electromagnetic cooker according to the present invention may be provided with a protective layer (glass coat layer or the like) for covering the heat generating layer. By providing the protective layer, the performance of preventing damage (wear, peeling, etc.) of the heat generating layer can be improved. Further, it is possible to better suppress the alteration of the conductive metal forming the heat generating layer. In a container for an electromagnetic cooker having a protective layer, the preferable average thickness of the heating layer is about 15
.About.50 .mu.m, with a more preferred average thickness being approximately 20 to 35 .mu.m. By setting the thickness of the heat generating layer in such a range, it is difficult for the protective layer to change in appearance such as penetration (cracking). Therefore, the durability of the electromagnetic cooker container is further improved.

The heating layer may contain at least one metal oxide selected from bismuth oxide, copper oxide, manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide and tungsten oxide. A preferable content of the metal oxide is an amount corresponding to approximately 0.1 to 30% of the mass of the conductive metal.

According to such a heating layer, the following (1).
(3). At least one effect can be obtained. (1). The durability can be excellent even when the thickness of the heat generating layer is relatively large. For example, in comparison with a heating layer having a composition containing glass frit instead of a metal oxide, even when this container is repeatedly used (that is, repeatedly exposed to a cooling / heating cycle), the heating layer floats or peels off. Is unlikely to occur. Therefore, the thickness of the heat generating layer can be increased. (2). In a container for an electromagnetic cooker having a structure in which the heat generating layer is covered with a protective layer (such as a glass coat layer), even if the thickness of the heat generating layer is relatively large, penetration into the protective layer is unlikely to occur. Therefore, the thickness of the heat generating layer can be increased. (3). When the thickness of the heat generating layer is about the same, as compared with a heat generating layer having a conventional composition containing glass frit instead of the metal oxide, an output equal to or higher than that of the conventional composition (in a more preferable embodiment, the conventional composition has It is possible to obtain a larger output than that of the heat generating layer). Due to at least one of the above effects (1) to (3), the container for an electromagnetic cooker of the present invention may include a heat generating layer having an improved output per unit area.

Preferred metal oxides contained in the heat generating layer are bismuth oxide and / or copper oxide,
The most preferred metal oxide is bismuth oxide. In this case, the effects of (1) to (3) above are great. Also, the appearance (color tone, etc.) of the heat generating layer is good.

According to the present invention, there is provided a paste for forming a heat generating layer of an electromagnetic cooker container. This paste contains a metal powder containing a conductive metal as a main component. The metal powder is an oxide ceramics source compound (oxide ceramics or a compound that can be converted to oxide ceramics by firing) on the surface of fine particles made of a conductive metal.
Are substantially composed of coated particles. Such a paste is suitable for use in forming a heat generating layer provided in any of the electromagnetic cooker containers of the present invention.

The metal powder preferably contains the oxide ceramics source compound in an amount (as oxide) equivalent to approximately 0.005 to 10% of the total mass of the fine particles. Further, Ag or an alloy mainly containing Ag is preferable as the conductive metal.

In a preferred one of the pastes of the present invention, the particles forming the metal powder are mainly flakes. With such a paste, it is possible to form a heat generating layer having excellent durability (for example, peeling of the heat generating layer is less likely to occur even when repeatedly exposed to a temperature change in a use situation). it can.

As the oxide ceramics source compound, for example, oxide ceramics having any of the elements selected from the group consisting of Al, Zr, Ti, Y, Ca, Mg and Zn as constituent elements, and heating these ceramics At least one selected from the group consisting of compounds that can be oxide ceramics can be used. The oxide ceramics source compound preferably used is at least one selected from the group consisting of alumina, zirconia, and compounds capable of forming these oxide ceramics by heating. A particularly preferred oxide ceramic source compound is alumina and / or zirconia.

The heat generating layer is at least selected from the group consisting of bismuth oxide, copper oxide, manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide, tungsten oxide, and compounds which become these metal oxides by heating. It may contain one type of metal oxide source compound (typically a powdered metal oxide source compound). The preferable content of the metal oxide source compound is an amount corresponding to approximately 0.5 to 25% (as oxide) of the mass of the metal powder.

As the metal oxide source compound, it is preferable to use one or more of bismuth oxide, copper oxide, and compounds capable of becoming these metal compounds by heating. The metal oxide source compound more preferably used is bismuth oxide and / or a compound capable of becoming bismuth oxide by appropriate heating, and the most preferable metal oxide source compound is bismuth oxide.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below. It should be noted that technical matters other than the contents particularly referred to in the present specification and necessary for implementing the present invention can be grasped as design matters for those skilled in the art based on the conventional technology. The present invention can be carried out based on the technical contents disclosed in this specification and the common general technical knowledge in the field.

The container body constituting the container for an electromagnetic cooker according to the present invention is mainly made of a non-metal material such as ceramics (typically porcelain mainly containing alumina) and heat-resistant glass. When the container body is made of ceramics, it is usually preferable that the surface of the container body is glazed. It is preferable that a heating layer is formed on the surface (surface) of the glaze. As the glaze, conventionally known ones can be used.
Examples of preferable glazes include those mainly containing lead-free borosilicate glass. Although not particularly limited, it is preferable that the container body is provided with a hill. In this case, it is easy to hold the bottom surface of the tableware or other cooking container with hands (easy to hold) without touching the heat generating layer. Height of hill (height from the flat surface of the bottom of the container)
Can be, for example, 0.5 to 5 mm, with a preferred height of 1 to 3 mm. If the height of the plateau is too large, it becomes difficult to obtain high output because the distance from the cooker surface to the heat generating layer when the container is set on the electromagnetic cooker becomes large.

A heating layer is provided on the bottom of the container body. Here, the “heating layer” typically refers to one continuous layer, but is also a term that includes a layer composed of two or more heating portions composed mainly of the above-mentioned conductive metal. Further, in the present specification, the “bottom portion” refers to a portion located on the lower side when the container for an electromagnetic cooker is used (that is, a portion which is close to the electromagnetic cooker and can generate heat). For example, the bottom of the container body or the part of the wall surface following this bottom that is close to the bottom (typically the bottom of the container body) is the "bottom".
Corresponds to. Further, in the present specification, “cooking” refers to general treatment (including heat retention) of heating food and drink.

The heat generating layer is the outer surface of the bottom (refers to the outer surface of the container body. If it is the bottom of the container body, it means the bottom surface).
May be provided on the inner surface (or the inner surface of the container body). Alternatively, a heat generating layer may be provided (embedded) inside the container body (inside the wall surface) that constitutes the bottom portion. Usually, it is preferable to provide a heat generating layer on the outer surface (particularly the bottom surface) of the container body. The preferable range of formation of the heat generating layer depends on the shape of the container and the like. When the container body is provided with a plateau, it is preferable to provide a heat generating layer on a portion of the bottom face surrounded by the plateau (inside the plateau). Such a container is easy to hold (easy to handle)
This is because. It should be noted that the heat generating layer can be provided in a portion other than the bottom portion. That is, the heat generating layer may be provided in at least a partial area of the bottom of the container body.

The container for an electromagnetic cooker according to the present invention may further include a protective layer for covering the heat generating layer. As the protective layer, a layer mainly composed of a glass component (glass coat layer) is preferable. FIG. 1 shows an example of a container (tableware) for an electromagnetic cooker including a heating layer and a protective layer. The tableware body 10 is made by applying a glaze (not shown) to the surface of a base body made of alumina reinforced porcelain or the like. A table 16 having a height of about 2 mm is formed on the bottom surface of the tableware body 10. A heating layer 20 is provided on the bottom surface of the tableware body 10 located inside the plateau 16. The area where the heat generating layer 20 is provided has a diameter of about 65 mm.
It has a circular shape. Further, a glass coat layer 30 that covers the heat generating layer 20 is provided.

Next, the structure of the heat generating layer and the manufacturing method will be described in detail. The heat generating layer provided in the container for an electromagnetic cooker according to the present invention is formed by sintering a metal powder mainly composed of a conductive metal. The sintered metal powder is substantially composed of coated particles in which oxide ceramics are coated on the surface of fine particles made of a conductive metal (hereinafter, also referred to as “base fine particles”). Here, the metal powder is “substantially composed of coated particles” means that most of the particles constituting the metal powder (for example, 50% by number or more, preferably 70% by number or more, particularly preferably 85% by number). (Above) means that they are coated particles. Here, the term "coating" does not mean that the particle surface is completely covered, but that a layer made of the oxide ceramic is formed on a part (preferably 50% or more of the surface area) of the particle surface. Say.

The heat-generating layer formed by sintering such metal powder is fired (for example, a heat-generating layer-forming paste described later is fired) because the metal powder is substantially composed of coating particles. "When it forms a heat-generating layer), there is little" burning ". Therefore, the stress generated at the boundary between the heat generating layer and the container body due to the shrinkage is reduced. As a result, even when the thickness of the heating layer is made relatively large (for example, when the average thickness of the heating layer is about 20 μm or more, typically 20 to 50 μm), the heating layer floats from the container body. The effect of improving the performance of suppressing the phenomenon of peeling and peeling is obtained. This effect is
It may be exhibited for the exothermic layer immediately after firing and / or after aging (for example, after repeated use of the container). This improves the durability of the heat generating layer. Further, in the configuration including the protective layer that covers the heat generating layer, since there is little shrinkage at the time of firing as described above, the stress generated at the boundary between the heat generating layer and the protective layer due to this shrinkage is also small. Become. As a result, even when the thickness of the heat generating layer is made relatively large (for example, when the average thickness of the heat generating layer is about 20 μm or more, typically 20 to 35 μm), penetration or the like occurs in this protective layer. Can be better prevented.

Since the surface of the conductive metal (base particles) is coated with the oxide ceramics in such a heat generating layer, the durability is excellent even in the structure having no protective layer for covering the heat generating layer. Indicates. For example, it is possible to suppress alteration of the conductive metal forming the heat generating layer (chemical change such as oxidation and sulfide, change in color tone) over a long period of time. Further, when the protective layer is provided, its durability (particularly durability against mechanical stress) is further improved.

Among the metal powders contained in the heat generating layer, as the conductive metal forming the base fine particles, for example, silver (A
It is possible to use one or more selected from g), copper (Cu), nickel (Ni), and an alloy mainly containing at least one of these metals. From the viewpoint of cost and low electric resistance, Ag or an alloy mainly composed of Ag (A
g-Pt alloy, etc.) is preferred.

The surfaces of such base fine particles are coated with oxide ceramics to form coated particles. As the oxide ceramics, for example, those having a constituent element of any element selected from the group consisting of Al, Zr, Ti, Y, Ca, Mg and Zn can be selected. Of these, alumina and / or zirconia are preferred. The coating amount of the oxide ceramics can be set to, for example, an amount corresponding to approximately 0.001 to 10% of the mass of the base fine particles (in other words, the oxide ceramics approximately 0. 001 to 10 parts by weight are coated). A preferable coating amount is an amount corresponding to approximately 0.005 to 10% by mass of the base fine particles, more preferably approximately 0.01 to 2%,
It is more preferably about 0.02 to 1%, particularly preferably about 0.05 to 0.5%.

It is preferable that the shape of the particles constituting the metal powder is mainly flake. The heat generating layer formed by sintering such metal powder has good adhesive strength (adhesive strength) to the container body. This can further enhance the effect of suppressing the heat generation layer from floating or peeling from the container body.

The heat generating layer may also contain oxide ceramics that do not form coating particles. The amount of the oxide ceramics contained in the heat generating layer (the total amount of the oxide ceramics which is not coated on the base fine particles) is, for example, the amount of the conductive metal contained in the heat generating layer. The amount may be approximately 0.001 to 10% (in other words, approximately 0.001 to 10 parts by mass of the oxide ceramic is contained with respect to 100 parts by mass of the conductive metal). A preferable content of the oxide ceramics is an amount corresponding to approximately 0.005 to 10% by mass of the conductive metal, more preferably approximately 0.01 to 2%, and further preferably approximately 0.02 to 1%. , Particularly preferably about 0.05
~ 0.5%. Although not particularly limited, most of oxide ceramics contained in the heating layer (for example,
It is preferable that 80% by mass or more of the entire oxide ceramics contained in the heat generating layer is contained in the heat generating layer in a state of being attached to the surface of the particles mainly composed of the conductive metal.

The heat generating layer usually contains an inorganic additive component in addition to the conductive metal and oxide ceramics. A typical example of the inorganic additive component is a glass component used in a general glass frit. The glass component preferably has a softening point of about 800 ° C. or lower (more preferably about 700 ° C. or lower). Examples of such glass components include lead-based, zinc and borosilicate-based glasses. Of these, lead-free ones are preferable, and a glass component mainly composed of lead-free borosilicate low-melting glass (preferably having a softening point of about 650 ° C. or lower) is particularly preferable.

As a preferred example of the inorganic additive component that can be contained in the heat generating layer of the present invention, bismuth oxide (Bi
₂ O ₃ etc.), copper oxide (CuO etc.), manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide and at least one metal oxide selected from tungsten oxide. Among these particularly preferable are bismuth oxide (Bi ₂ O ₃₎ and / or copper oxide (CuO), and most preferred are bismuth oxide (Bi ₂ O _3).

Generally, a conductive metal (A
g) has a larger coefficient of thermal expansion than a material (a base material such as ceramics or a glaze) forming the surface of the container body. A heating layer containing a specific metal oxide as described above is, for example, compared to a heating layer containing the same amount of glass (for example, a low melting point glass used in a general glass frit) instead of the metal oxide. The coefficient of thermal expansion may be small. Therefore, the difference in coefficient of thermal expansion between the heat generating layer and the container body can be reduced. As a result, the stress generated between the heat generating layer and the container body due to the temperature change of the electromagnetic cooker container is reduced. As a result, even when this container is repeatedly used (exposed to a cooling / heating cycle), the phenomenon that the heat generating layer floats or peels off from the container body is further suppressed. Similarly, in the container for an electromagnetic cooker in which the heat generating layer is covered with the protective layer, the difference in the coefficient of thermal expansion between the heat generating layer and the protective layer can be reduced by including the metal oxide. This reduces the stress generated between the heat generating layer and the protective layer due to the temperature change of the electromagnetic cooker container. As a result, even when this container is repeatedly used, the occurrence of phenomena such as penetration, swelling, and peeling of the protective layer is further suppressed. Therefore, the container for an electromagnetic cooker excellent in durability and aesthetics can be obtained.

As another container for an electromagnetic cooker provided by the present invention, a container body made of a non-metallic material and a heat generating layer provided at the bottom of the container body are provided and sintered. The metal powder is substantially composed of coated particles in which oxide ceramics (typically alumina and / or zirconia) are coated on the surface of fine particles made of a conductive metal (typically Ag), This heat generating layer contains one or more metal oxides having a thermal expansion coefficient smaller than that of a glass frit (for example, a general low-melting glass) to approximately 0.1% of the conductive metal.
A container for an electromagnetic cooker containing an amount corresponding to ˜30% (more preferably about 1 to 15%, further preferably about 1.5 to 10%) can be mentioned. Here, as the metal oxide, for example, one having a coefficient of thermal expansion of approximately 1 × 10 ⁻⁵ / ° C. or less (typically approximately 1 × 10 ⁻⁶ to 1 × 10 ⁻⁵ / ° C.) is used. You can Even with such a heat generating layer, the difference in the coefficient of thermal expansion between the heat generating layer and the container body and / or the protective layer can be reduced. Therefore, the effect of suppressing floating and peeling of the heat generating layer and / or the effect of preventing penetration or the like from occurring in the protective layer are improved.

The mass of the above-mentioned specific metal oxide contained in the heat generating layer of the present invention (when a plurality of metal oxides are contained, their total amount) is 0.1 to 30 of the mass of the conductive metal.
% Equivalent amount (in other words, about 0.1 to 30 parts by mass of metal oxide in total for 100 parts by mass of conductive metal)
Is preferable, and more preferably about 0.5 to 2
The amount corresponds to 0%, more preferably approximately 1 to 10%. When the content of the metal oxide is too small, the effect of suppressing the thermal expansion of the heat generating layer becomes small. On the other hand, when the content of the metal oxide is too large, the electric resistance of the heat generating layer becomes high. Therefore, the output tends to decrease.

The heat generating layer provided in the container of the present invention may have a composition that does not substantially contain a glass component (typically, a low-melting glass such as glass frit). Alternatively, a glass component may be contained within a range that does not significantly impair the effects of the present invention (for example, the effect of suppressing floating and peeling of the heat generating layer). The proportion of the glass component contained in the heat generating layer is preferably an amount corresponding to approximately 15% or less of the mass of the conductive metal, more preferably approximately 5%.
Or less, more preferably about 1% or less. When the heat generating layer contains the specific metal oxide and the glass component, the total amount thereof is approximately 20% (more preferably approximately 15%) of the mass of the conductive metal. It is preferable not to exceed significantly.

The ratio of the conductive metal (or the total of the conductive metals when a plurality of conductive metals are contained) to the total mass of the heat generating layer can be about 60% by mass or more, and about 7% by mass.
The amount is preferably 0 to 99.9% by mass, more preferably about 80 to 99.5% by mass, and further preferably about 90 to 99% by mass. If the content of the conductive metal is too low, the output may tend to decrease.

In addition, the heat generating layer may contain general inorganic and / or organic additives such as coloring agents, as long as the effects of the present invention are not significantly impaired.

The thickness of the heat generating layer provided in the container for the electromagnetic cooker can be, for example, in the range of about 10 to 100 μm as an average value. If the thickness of the heat generating layer is too small, the output tends to be low. On the other hand, if the thickness of the heat generating layer is too large, the durability may be lowered. For example, due to shrinkage during firing or repeated use, floating may occur in a part of the heat generating layer, or penetration may occur in the protective layer in the configuration including the protective layer. The preferable thickness of the heat generating layer is about 15 to 50 μm (more preferably about 2 to 50 μm) in a tableware (plate, bowl, cup, etc.) for an electromagnetic cooker having a protective layer.
0 to 35 μm). In the case of the tableware for the electromagnetic cooker that does not have the protective layer, the thickness of the heat generating layer is about 15 to 100 μm
(Preferably about 20 to 50 μm).

The heating layer-forming paste of the present invention is suitable for use in forming the heating layer provided in any of the containers of the present invention described above. Hereinafter, the composition and preparation method of this heating layer forming paste will be described.

The metal powder contained in the heating layer forming paste of the present invention is substantially composed of coated particles in which the surface of fine particles (base fine particles) made of a conductive metal is coated with an oxide ceramics source compound. There is. For example, 50% by number or more, preferably 70% by number or more, particularly preferably 85% by number or more of the particles constituting the metal particles are coated particles. As the conductive metal forming the base particles, the same conductive metal forming the heat generating layer can be used. A preferred conductive metal is Ag or an alloy mainly containing Ag.

The surface of the base fine particles is coated
Examples of the oxide ceramic source compound include
Group consisting of 1, Zr, Ti, Y, Ca, Mg and Zn
An oxide whose constituent element is any element selected from
Ceramics and heating these oxide ceramics
Use at least one of the compounds
be able to. "When heated, it becomes oxide ceramics
"Obtaining compound" constitutes its oxide ceramics
An organic acid salt of a metal atom (typically Al, Zr) (for example,
For example, acetate, carboxylate such as oxalate), inorganic acid salt
(Carbonate, nitrate, sulfate, phosphate, etc.), halogenated
Compounds, hydroxides, oxyhalides, etc.
Wear. For example, a suitable metal alkoxide is tet
Lapropoxy titanium (Ti (OC₃H ₇)_Four) Etc. titanium (IV) Arco
Xide, aluminum ethoxide (Al (OC₂H_Five)₃),Aluminum
N-t-butoxide (Al (OC (CH₃)₃)₃), Acetoalkoxy
Sialuminum diisopropylate, acetoalkoxy
Aluminum ethyl acetoacetate, acetoalkoxy
Aluminum such as sialuminium acetylacetonate
Alkoxide, zirconium ethoxide, zirconium
In addition to zirconium alkoxides such as butoxide, Zn,
Various kinds of metal such as Mg and Ca as central metal atoms (ions)
A nuclear alcoholate complex is mentioned. Also a suitable chelate
As the compound, Zn, Mg, Ca, etc. are central metal atoms.
(Ion) ethylenediamine (en) complex, ethylene
Examples thereof include a diamine tetraacetate (edta) complex. Ah
Ru, metal (ion) such as Ti, Zn, Mg
The so-called chelate resin that forms the oxide
It can also be used as a compound. In the paste of the present invention
Oxide ceramics that form coating particles
As the source compound, oxide ceramics (especially alumina)
And / or zirconia) are preferred.

The metal powder contains, for example, an oxide ceramics source compound in an amount (as oxide) equivalent to approximately 0.001 to 10% of the mass of the base fine particles (in other words, 100 parts by mass of the base fine particles). In contrast, the oxide ceramics source compound contains approximately 0.001 to 10 parts by mass). That is, the coating amount of the oxide ceramics source compound (as oxide) corresponds to approximately 0.001 to 10% of the mass of the base fine particles. A preferable coating amount (as oxide) is an amount corresponding to approximately 0.005 to 10% of the mass of the base fine particles, more preferably approximately 0.01 to 2%, still more preferably approximately 0.02 to 1%. Particularly preferably about 0.05
~ 0.5%. If the coating amount of the oxide ceramics source compound is less than the above range, it becomes difficult to obtain a remarkable effect. On the other hand, if the coating amount of the oxide ceramics source compound is more than the above range, the output of the heat generating layer tends to decrease, which is not preferable.

The shape of the particles constituting this metal powder is preferably mainly flake. For example, 70% by number or more of the particles constituting the metal powder are preferably flaky particles (for example, the ratio of the thickness to the long side of the particles is 0.5 or less). The paste containing such metal powder can form a heat generating layer having good adhesive strength (adhesive strength) to the container body.

Although not particularly limited, this metal powder has, for example, an average particle size (by BET method) of 5 μm.
Those having a particle size of m or less (typically, an average particle size of 0.5 to 5 μm) can be used. When the shape of the metal powder is mainly flake-like, it is preferable that the flake-like particles have an average major axis of 1 to 10 μm and an average thickness of 0.1 to 2 μm. In addition, when the coating amount of the oxide ceramics source compound is relatively small (for example, when the coating amount in terms of oxide is an amount corresponding to approximately 2% or less of the mass of the base fine particles), the above-described preferable average particle size is preferable. Diameter or shape (flatness, size, etc. of flaky particles)
Can be produced by coating the surface of the base fine particles having an average particle diameter or shape approximately the same as those with the oxide ceramic source compound.

The method for producing the coated particles is not particularly limited, but the following method (i) or (ii) is exemplified as a preferable method. Of these, the method (i) below is particularly preferable.

(I) A sol of oxide ceramics (typically alumina sol, zirconia sol, etc.) is prepared. In addition, a predetermined amount of base fine particles mainly composed of a conductive metal (typically Ag) is weighed. While stirring the sol of oxide ceramics, a predetermined amount of base fine particles mainly composed of a conductive metal (typically Ag) is charged and dispersed / suspended. This suspension is left standing or stirred for a predetermined time. This is dried to obtain coated particles.

(Ii) A compound which becomes an oxide ceramic by heating (for example, a carboxylate of Al or Zr) is dissolved or dispersed in a suitable solvent. Base microparticles are added to this solution or dispersion (sol) to disperse and suspend. This suspension is left standing or stirred for a predetermined time. This is dried to obtain coated particles.

The paste of the present invention may also contain an oxide ceramics source compound that does not form coating particles (free; for example, in a state of being dispersed in a solvent). The total amount of oxide ceramics source compounds contained in the paste (as oxide) can be, for example, an amount corresponding to approximately 0.001 to 10% of the mass of the conductive metal, and approximately 0.005. -10% (more preferably about 0.01 to 2%, even more preferably about 0.0
2 to 1%, particularly preferably about 0.05 to 0.5%) is preferable. Further, it is preferable that most of the oxide ceramics source compound (for example, 80% by mass or more) is contained in the paste as coating particles.

The paste of the present invention usually contains an inorganic additive in addition to the conductive metal and oxide ceramics. A typical glass frit is a typical example of the inorganic additive. The preferred types of glass components that compose the glass frit are the same as the glass components that can be included in the heat generating layer described above.

As a preferable example of the inorganic additive that can be contained in the paste of the present invention, bismuth oxide (Bi ₂
O ₃ etc.), copper oxide (CuO etc.), manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide and tungsten oxide and by heating (typically when this paste is fired to form a heat generating layer). Mention may be made of at least one metal oxide source compound selected from the group consisting of the compounds which, upon heating, can form these metal oxides. Examples of the “compound capable of forming these metal oxides by heating” include bismuth (Bi), copper (Cu), manganese (Mn), cobalt (Co), magnesium (M
g), tantalum (Ta), niobium (Nb) and tungsten (W) organic acid salts (for example, carboxylates such as acetate and oxalate), inorganic acid salts (carbonate, nitrate, sulfate, phosphoric acid) Salts, etc.), metal alkoxides, chelate compounds, halides, hydroxides, oxyhalides and the like can be used. Among these, preferable metal oxide source compounds are bismuth oxide (Bi ₂ O ₃ ), copper oxide (Cu
O) and one or more compounds that become these metal compounds by appropriate heating. A more preferable metal oxide source compound is bismuth oxide and / or a compound which becomes bismuth oxide (Bi ₂ O ₃ ) by heating, and the most preferable metal oxide source compound is bismuth oxide (Bi ₂ O ₃ ).

Although not particularly limited, the metal oxide source compound has, for example, an average particle size (by BET method) of 5 μm or less (typically, an average particle size of 0.1 to 5 μm).
m) (powder) can be used. A preferable average particle size of the metal oxide source compound is 1 μm or less (typically, an average particle size of 0.1 to 1 μm). The paste of the present invention preferably contains a metal oxide source compound in an amount corresponding to approximately 0.5 to 25% (as oxide) of the mass of the metal powder. A more preferable content is an amount corresponding to approximately 1 to 15% of the mass of the metal powder.

The paste of the present invention may have a composition that does not substantially contain a glass component (typically, a low-melting glass such as glass frit). Alternatively, a glass component may be contained within a range that does not significantly impair the effects of the present invention. The proportion of the glass component contained in the paste is preferably an amount corresponding to approximately 15% or less (more preferably approximately 5% or less, further preferably approximately 1% or less) of the mass of the conductive metal. When the heating layer contains the metal oxide source compound and the glass component, the total amount of these (the metal oxide source compound is calculated as an oxide) is 20% of the mass of the conductive metal ( More preferably, it does not significantly exceed an amount corresponding to 15%).

The pastes of the present invention typically contain an organic binder and a suitable amount of solvent. As the organic binder, those based on acrylic resin, epoxy resin, phenol resin, alkyd resin, cellulosic polymer and the like can be used. Among these, those based on acrylic resin are preferably used.

In addition, the paste may contain general inorganic and / or organic additives such as colorants, thickeners, and dispersants, as long as the effects of the present invention are not significantly impaired. .

The heating layer-forming paste of the present invention can be prepared by a conventional method. For example, by using a three-roll mill or other kneading machine, the metal powder and the organic binder solution (organic binder dissolved in a solvent) are directly mixed at a predetermined mixing ratio and kneaded with each other, thereby The paste can be easily prepared. At this time, the above-mentioned additives (inorganic additives, etc.) may be added and mixed as necessary. The amount of the organic binder solution used for preparing the paste is approximately 5 to about 5% of the whole paste.
An appropriate amount is 40% by mass,
An amount of 30% by mass is preferable, and an amount of 15 to 25% by mass is particularly preferable. The metal powder used for preparing the paste may be, for example, the above-mentioned (i) or (ii).
Those produced by applying the method for producing coated particles can be used.

In order to obtain a container for an electromagnetic cooker according to the present invention using such a heating layer forming paste, a film made of the heating layer forming paste is attached to a predetermined portion (typically the bottom surface) of the container body. Then, this may be fired. Thereby, the heat generating layer can be provided on the surface of the container body. It is preferable to use a transfer method (typically a wet transfer method) as a method for attaching the coating film made of the heating layer forming paste to the container body. For example, the heating layer forming paste is applied on a mount and dried to form a dry paste film on the mount. This dry paste film may be transferred to the surface of the container body. Such a transfer method is particularly suitable for forming a heat generating layer in a wide range inside the plateau (for example, in a range of 70 area% or more of the inner part of the plateau).

The method of forming the heat generating layer is not limited to this. For example, the heating layer forming paste may be directly applied to the container surface by a screen printing method or the like, and the applied paste may be dried and then fired to form the heating layer. In the case of the heat-generating layer forming paste having a typical composition, the thickness (printing thickness) of the dry paste film for obtaining a heat-generating layer (after firing) having an average thickness of about 15 to 20 μm is about 40 μm.
It is about m. Further, the thickness (printing thickness) of the dry paste film for obtaining the heat generating layer (after firing) having an average thickness of about 20 to 25 μm is about 50 μm.

The electromagnetic cooker container of the present invention may be provided with a protective layer for covering the heat generating layer. By providing this protective layer, the mechanical durability (wear, peeling, etc.) and / or the chemical durability (chemical change such as oxidation, sulfuration, change in color tone, etc.) of the heat generating layer is improved. The thickness of the protective layer is not particularly limited, but is usually 3 to 30 as an average value.
The thickness is preferably about μm.

The protective layer is preferably a glass coat layer composed mainly of a glassy material. As the glass component forming the glass coat layer, the same glass component as that which can be contained in the heat generating layer can be used. A glass coat layer made of lead-free borosilicate low-melting glass (preferably having a softening point of about 650 ° C. or lower) is particularly preferable. Such a glass coat layer can be obtained, for example, by adding glass powder (glass frit) to an organic binder solution.
It can be produced by applying and firing a paste (glass paste) in which is dispersed. As the organic binder solution used for preparing the glass paste, the same one as the heating layer forming paste (for example, one based on acrylic resin) can be used.

In order to obtain a container for an electromagnetic cooker in which a protective layer is provided on the heating layer, for example, the heating layer forming paste is applied on the mount as described above and dried to form a dry paste film. After the formation, a protective layer forming paste (typically a glass paste) is applied from above and dried. This laminated film may be transferred onto the surface of the container body and baked. In this case, the heat generating layer and the protective layer are simultaneously fired. Alternatively, the heating layer-forming paste may be first transferred and fired on the surface of the container body, and then the protective layer-forming paste may be transferred and fired on the obtained heating layer to form the protective layer.

The present invention can be applied to dishes of various shapes such as dishes, bowls, cups and the like. In particular, it is preferably applied to Japanese tableware such as bowls, bowls, pots and hot water, and tableware having a small diameter such as various cups and sake bottles. The present invention is not limited to tableware, but can be applied to cooking utensils (for example, pots and pans) for electromagnetic cookers.

[0064]

EXAMPLES Hereinafter, some examples of the present invention will be described, but the present invention is not intended to be limited to those shown in the examples.

<Experimental Example 1: Preparation of ZrO ₂ coating powder> Metal powders (a) to (c) substantially composed of coated particles coated with zirconia (ZrO ₂ ) were prepared as follows. did. That is,
Flake-shaped Ag particles (base fine particles) were added to the zirconia sol and dispersed / suspended. The suspension was stirred for a predetermined time and then dried. In this way, substantially constructed metallic powder of particles the surface of the Ag particles are coated with ZrO ₂ (coated particles) (hereinafter,
Also referred to as "coating powder". ) Got. Three types of ZrO ₂ coating powders having different zirconia contents were prepared by adjusting the amount of Ag particles to be added to the zirconia sol. The coating powder (a) contains ZrO _{2 in} an amount corresponding to about 0.05% of the mass of the Ag particles (base particles) (in other words, 0.05 parts by mass of ZrO _{2 with} respect to 100 parts by mass of the base particles). Contains. The coating powder (b) also contains ZrO ₂ in an amount corresponding to about 0.1% of the mass of Ag particles. The coating powder (c) contains Z in an amount corresponding to about 0.2% of the mass of Ag particles.
It contains rO ₂ . The zirconia sol containing Ag particles can be prepared by using a commercially available zirconia sol (for example, the zirconia sol as it is, or by diluting or concentrating appropriately).

<Experimental Example 2: Preparation of Al ₂ O ₃ coating powder> Coated particles coated with alumina (Al ₂ O ₃ ) in the same manner as in Experimental Example 1 except that alumina sol was used instead of zirconia sol. The coating powders (d) to (f) substantially composed of Three kinds of Al ₂ O ₃ coating powders having different alumina contents were prepared by adjusting the amount of Ag particles to be added to the alumina sol. Coating powder (d)
Contains Al ₂ O ₃ in an amount corresponding to about 0.05% of the mass of Ag particles (base particles). The coating powder (e) also contains Al ₂ O ₃ in an amount corresponding to about 0.1% of the mass of Ag particles. Coating powder (f) is Ag
It contains Al ₂ O ₃ in an amount corresponding to about 0.2% of the mass of the particles. The alumina sol to which Ag particles are added can be prepared using a commercially available alumina sol (for example, the alumina sol as it is, or by appropriately diluting or concentrating).

<Experimental Example 3: Preparation of paste using coating powder> 68 parts by mass of the coating powder (a) obtained in Experimental Example 1 and 23.6 parts by mass of an organic binder solution were mixed to prepare a paste (A ) Was prepared. As the organic binder solution, an organic solvent solution of acrylic resin (acrylic resin content ratio: 25 to 30% by mass) was used. Similarly, 68 parts by mass of the coating powders (b) to (f) obtained in Experimental Example 1 or Experimental Example 2 and the organic binder solution 2 were used.
3.6 parts by mass were mixed to prepare pastes (B) to (F).

<Experimental Example 4: Preparation of paste using uncoated powder> Using the same Ag particles (base fine particles; not coated with ZrO ₂ ) used in Experimental Example 1, paste (G) was used. Prepared. That is,
68 parts by mass of a metal powder (Ag powder) composed of Ag particles and an organic binder solution (the same as in Experimental Example 3) 23.6
And parts by weight.

<Experimental Example 5: Preparation and evaluation of test piece (1)> Pastes (A) to
(G) was applied onto a mount so that the printed thickness was about 50 μm. A screen printing method was used as a method for applying the paste. After drying the applied pastes (A) to (G), this dry paste film was transferred onto the surface of the substrate by a wet transfer method and dried. Here, as the base material, an alumina flat plate having a surface coated with glaze was used. The size (forming range) of the dried paste film after drying was circular with a diameter of 19.54 mm. This dry paste film was fired at each temperature of 800 ° C, 850 ° C and 900 ° C. Shrinkage rate (%) as an index of firing shrinkage by measuring the diameter of the coating (heating layer) formed after firing and comparing it with the diameter of the dry paste coating before firing
Was calculated. The results are shown in Table 1. Table 1 also shows the types of metal powder and paste used.

[0070]

[Table 1]

As can be seen from Table 1, as compared with the paste (G) (test piece 7) prepared using uncoated metal powder (Ag powder), ZrO ₂ coating powder or Al ₂ O ₃ coating powder was used. Each of the pastes (A) to (F) (test pieces 1 to 6) prepared by using the method had a small baking shrinkage (shrinkage rate). The amount of oxide ceramics contained in the metal powder is 0.
In the range of the amount corresponding to 05 to 0.2%, there was a tendency that the firing shrinkage became smaller as the content of the oxide ceramics increased.

<Experimental Example 6: Preparation of paste using coating powder> Coating powder (e) prepared in Experimental example 2 (A in an amount corresponding to about 0.1% of the mass of Ag particles)
70 parts by mass (containing 1 ₂ O ₃ ), 10 parts by mass of glass frit and an organic binder solution (the same as in Experimental Example 3) 2
0 mass part was mixed and the paste (H) was prepared. As the glass frit, lead-free borosilicate low melting point glass (softening point of about 550 ° C.) was used. Similarly, 70 parts by mass of the coating powder (e), 5 parts by mass of the glass frit and 25 parts by mass of the organic binder solution (the same as in Experimental Example 3) were mixed to prepare a paste (I).

<Experimental Example 7: Preparation and evaluation of test piece (2)> In the same manner as in Experimental Example 5, the paste (H) was applied onto a mount and dried. The diameter of the dry paste film is about 85
mm. From there, glass paste is generally 16-18
It was applied at a thickness of μm (printing thickness) and dried. The glass paste was applied by screen printing. The glass paste was prepared by mixing the same glass frit used in Experimental Example 6 with the same organic binder solution used in Experimental Example 3 at a mass ratio of about 45/55. Furthermore, it was covered with a resin layer. Transfer this laminated film to the surface of the tableware body by a wet transfer method,
It was baked at 850 ° C. As the tableware body, a main dish (tableware body) having a height of 100 mm and a height of 2 mm was used. In this manner, a plurality of dishes for electromagnetic cookers (test pieces) in which heat-generating layers having different thicknesses were provided and each heat-generating layer was covered with the protective layer (glass coat layer) were produced. When visually observing the appearance of those tableware for an electromagnetic cooker, the printed thickness is at least about 60 μm.
(The thickness of the heat generating layer is about 25 to 30 μm) In the range of about the following or less, floating or peeling of the heat generating layer was not observed. In addition, no penetration was observed in the protective layer.

<Experimental Example 8: Preparation and Evaluation of Test Piece (3)> In the same manner as in Experimental Example 5, the paste (I) was applied onto a mount and dried. This coating has print thicknesses of about 19 μm, 30 μm, 49 μm, 62 μm and 83 μm, respectively.
I went to m. It was covered with a resin layer. This laminated film was transferred onto the surface of the tableware body (the same as in Experimental Example 7) by a wet transfer method, and baked at 850 ° C. Thus, the thickness of the heat generating layer is about 8.3 μm, 13 μm, 20.
A plurality of dishes for electromagnetic cookers (test pieces 8 to 12) having a thickness of 3 μm, 24.8 μm, and 34.9 μm and having no protective layer for covering the heating layer were prepared. When visually observing the appearance of the dishes for the electromagnetic cooker, at least the printed thickness is about 80 μm (the thickness of the heating layer is about 30 to
In the range of about 40 μm) or less, the heating layer was not lifted or peeled off.

The obtained electromagnetic cooker tableware (test pieces 8 to 1)
The heating performance of 2) was evaluated. That is, 200 ml of water was put in each dish for electromagnetic cookers and set in the electromagnetic cooker, and the time until the water was heated to 75 ° C. (temperature rising time) was measured under the same conditions. The results are shown in Table 2 together with the print thickness of the paste (I) and the heat generation thickness. As can be seen from Table 2, as the thickness of the heat generating layer is increased, the heating time can be shortened significantly.

[0076]

[Table 2]

<Experimental Example 9: Preparation of paste using coating powder> The coating powder (f) produced in Experimental Example 2 (A in an amount corresponding to about 0.2% of the mass of Ag particles) was used.
A paste (J) is prepared by mixing 70 parts by mass (containing 1 ₂ O ₃ ), 5 parts by mass of glass frit (the same as in Experimental Example 6) and 25 parts by mass of an organic binder solution (the same as in Experimental Example 3). did. Similarly, coating powder (b)
(Amount of ZrO ₂ corresponding to about 0.1% of the mass of Ag particles
70 parts by mass), 5 parts by mass of the glass frit and 25 parts by mass of the organic binder solution were mixed to prepare a paste (K). In addition, coating powder (c) (A
A paste (L) was prepared by mixing 70 parts by mass (containing ZrO ₂ in an amount corresponding to about 0.2% by mass of g particles), 5 parts by mass of glass frit and 25 parts by mass of an organic binder solution.

<Experimental Example 10: Preparation and evaluation of test piece (4)> Tableware having a heat generating layer without a protective layer was prepared, and the degree of discoloration with time of the heat generating layer was evaluated.
That is, in the same manner as in Experimental Example 8, the paste (J),
Tableware for electromagnetic cookers (test pieces 13 to 15) having the heating layer formed by using (K) and (L) and not having the protective layer covering the heating layer was prepared. Also, 68 parts by mass of the same Ag powder (consisting of Ag particles not coated with oxide ceramics), 5 parts by mass of glass frit, and 25 parts by mass of an organic binder solution (the same as in Experimental Example 3) used in Experimental Example 4 The parts were mixed to prepare a paste (M). Using this paste (M), tableware (test piece 16) for an electromagnetic cooker was prepared in the same manner as the pastes (J) to (L). These test pieces 14-
The thickness of the heat generating layer provided in 17 is approximately 20 μm. A test piece including a heat generating layer formed using paste (I) (test piece 10 obtained in Experimental Example 8) and a test piece including a heat generating layer formed using pastes (J) to (M). Therefore, the degree of discoloration of the heat generating layer with time was evaluated.
Specifically, the L value of the heating layer immediately after firing and left at room temperature for one month was measured using a color difference meter. The results are shown in Table 3 together with the type of paste used.

[0079]

[Table 3]

As can be seen from Table 3, the heating layers (test piece 10 and test pieces 13 to 15) formed by the pastes (I) to (L) prepared by using the coating powder,
Paste prepared using uncoated powder (M)
L compared to the heating layer (test piece 16) formed by
The degree of change in the value is obviously small. This means that by using coating powder as the raw material for the paste,
It is shown that the durability (performance of suppressing a change in color tone, etc.) of the heat generating layer is improved in the structure having no protective layer.

<Experimental Example 11: Preparation of paste using coating powder and bismuth oxide> In the same manner as in Experimental Example 1, an amount of Z corresponding to about 0.034% of the mass of Ag particles was obtained.
A ZrO ₂ coating powder (g) containing rO ₂ was prepared. 77 parts by mass of this coating powder (g), Bi ₂
A paste (N) was prepared by mixing 2.3 parts by mass of O ₃ powder and 20.7 parts by mass of an organic binder solution (the same as in Experimental Example 3).

<Experimental Example 12: Preparation of paste using uncoated powder and glass frit> 68 parts by mass of the same Ag powder as used in Experimental Example 4 (consisting of Ag particles not coated with oxide ceramics), A paste (O) was prepared by mixing 8.4 parts by mass of a glass frit (the same as in Experimental Example 6) and 23.6 parts by mass of an organic binder solution (the same as in Experimental Example 3).

<Experimental Example 13: Preparation and evaluation of test piece (5)> The heat generating layer forming pastes (N) and (O) obtained as described above were applied on a mount and dried. This coating was performed so that the printed thicknesses became the predetermined thicknesses (printed thicknesses) shown in Tables 4 to 9, respectively. A screen printing method was used as the coating method, and the coating range was a circle having a diameter of 65 mm. A glass paste (the same as that used in Experimental Example 7) was applied thereon to a thickness (printing thickness) of approximately 16 to 18 μm and dried. Furthermore, it was covered with a resin layer. This laminated film was used as a substrate by the wet transfer method (the same as in Experimental Example 5).
Transferred to the surface of. After the transfer was dried, it was baked on the surface of the substrate by baking at a predetermined temperature shown in the margins of Tables 4 to 9. In this way, a test piece in which the heating layer and the glass coat layer were provided on the surface of the base material was produced.

The resistance value and output of the obtained test piece were evaluated. That is, each test piece was placed on the cooking surface of the electromagnetic cooker, and changes in current and voltage before and after the placement were measured. Tables 4 to 9 show the evaluation results of the resistance value (mΩ) and the output (W) together with the type of paste used for producing the test piece, the printing thickness and the firing temperature.

[0085]

[Table 4]

[0086]

[Table 5]

[0087]

[Table 6]

[0088]

[Table 7]

[0089]

[Table 8]

[0090]

[Table 9]

As can be seen from Tables 4-6 and 7-9,
Comparing prints having similar print thicknesses, the test pieces (test pieces 21 to 35) having the heating layer formed of the paste (N) were formed of the paste (O) at any firing temperature. A test piece having a heating layer (test piece 3
6 to 50) and an output equal to or higher than that of the above. This indicates that by using the paste (N), it is possible to further reduce the thickness of the heat generating layer for obtaining an output comparable to that of the heat generating layer formed using the paste (O). Reducing the thickness of the heat generation layer means that the heat generation layer and the base material (tableware body)
And / or it is preferable from the viewpoint of reducing the stress generated between the glass coat layer (protective layer).

When the produced test pieces were visually observed, the test pieces (test pieces 21 to 35) obtained by using the paste (N) showed no penetration into the glass coat layer regardless of the printing thickness. I couldn't see it. On the other hand, test pieces (test pieces 36 to 50) obtained by using the paste (O)
Then, the printing thickness is about 40 μm or more (especially 45 μm or more)
Some of the test pieces in which the glass coat layer had penetrated were found in the sample. When the surfaces of the coating powders (a) to (g) produced in the above experimental example are observed by an electron microscope, it is found that a layer of alumina or zirconia (not shown) is formed on the surface of Ag particles (base fine particles). Was confirmed.

Specific examples of the present invention have been described above in detail, but these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. Further, the technical elements described in the present specification or the drawings are
The technical usefulness is exhibited alone or in various combinations, and is not limited to the combinations described in the claims at the time of filing. In addition, the technique illustrated in the present specification or the drawings achieves a plurality of purposes at the same time, and achieving the one purpose among them has technical utility.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing an example (tableware) of an electromagnetic cooker container of the present invention.

[Explanation of symbols]

10: Tableware body (container body) 20: Heating layer 30: Glass coat layer (protective layer)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Terada Sugiura             Noritake Shincho 3-chome 1-36, Nishi-ku, Nagoya-shi, Aichi             Noritake Co., Ltd. Limited             Within F-term (reference) 3K051 AB05 AD32 CD44                 4B055 AA09 BA14 DB14 FA16 FB15                       FB23 FC07

Claims (16)

[Claims] 1. A container main body made of a non-metallic material, and a heat generating layer provided on the bottom of the container main body, wherein the heat generating layer is formed by sintering a metal powder mainly composed of a conductive metal. A container for an electromagnetic cooker in which the sintered metal powder is substantially composed of coated particles in which oxide ceramics are coated on the surfaces of fine particles made of a conductive metal. 2. The oxide ceramics is Al, Z
The container for an electromagnetic cooker according to claim 1, wherein the container is at least one kind of oxide ceramics whose constituent element is any element selected from the group consisting of r, Ti, Y, Ca, Mg, and Zn. 3. The electromagnetic cooker according to claim 1, wherein the conductive metal is one or more selected from the group consisting of Ag, Cu, Ni and an alloy mainly containing at least one of these metals. container. 4. The electromagnetic wave according to claim 1, wherein the heat generating layer contains the oxide ceramics in an amount corresponding to approximately 0.005 to 10% of the mass of the conductive metal. Container for cooking equipment. 5. The heating layer has an average thickness of approximately 15 to 10.
The container for an electromagnetic cooker according to any one of claims 1 to 4, which has a range of 0 µm. 6. The heat generating layer comprises bismuth oxide, copper oxide,
A metal oxide containing at least one metal oxide selected from manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide and tungsten oxide.
The container for an electromagnetic cooker according to any one of to 5. 7. The dish for an electromagnetic cooker according to claim 6, wherein the content of the metal oxide is an amount corresponding to approximately 0.1 to 30% of the mass of the conductive metal. 8. The container for an electromagnetic cooker according to claim 6, wherein the metal oxide is bismuth oxide. 9. A paste for forming a heat generating layer of a container for an electromagnetic cooker, comprising a metal powder mainly composed of a conductive metal as a main component, wherein the metal powder is formed on the surface of fine particles composed of the conductive metal. A paste, which is substantially composed of coated particles coated with an oxide ceramics source compound, wherein the oxide ceramics source compound is an oxide ceramics or a compound capable of becoming an oxide ceramics by firing. 10. The paste according to claim 9, wherein the metal powder contains the oxide ceramics source compound in an amount (as oxide) equivalent to approximately 0.005 to 10% of the mass of the fine particles. 11. The paste according to claim 9, wherein the coated particles are mainly flakes in shape. 12. The oxide ceramics source compound comprises:
At least one selected from the group consisting of oxide ceramics containing any one of Al, Zr, Ti, Y, Ca, Mg and Zn as a constituent element and compounds capable of forming these oxide ceramics by heating. The paste according to any one of 9 to 11. 13. The conductive metal is Ag, Cu, Ni.
The paste according to any one of claims 9 to 12, which is one or more selected from the group consisting of alloys containing at least one of these metals as a main component. 14. At least one selected from the group consisting of bismuth oxide, copper oxide, manganese oxide, cobalt oxide, magnesium oxide, tantalum oxide, niobium oxide, tungsten oxide, and compounds capable of forming these metal oxides by heating. The paste according to any one of claims 9 to 13, which contains the metal oxide source compound of. 15. The content of the metal oxide source compound is
As an oxide equivalent, the mass of the metal powder is approximately 0.5 to
15. The paste according to claim 14, in an amount corresponding to 25%. 16. The paste according to claim 14, wherein the metal oxide source compound is bismuth oxide.