JPH07201462A - Upper plate for induction heating cooking device having temperature sensing discoloring pattern - Google Patents

Abstract

PURPOSE:To provide low hazardousness further with temperature control capable by forming a reversible temperature sensing discoloring pattern layer with 40 deg.C or more discoloring temperature in a surface of placing an induction heated object, and forming a transparent heat insulating layer on this surface. CONSTITUTION:A plate consisting of silicon nitride is used as an induction heating cooking device upper plate 1, and a plate of composition 1 is used in a surface of the cooking device upper plate 1, to form the first blue color temperature sensing discoloring pattern layer 2 at an ordinary temperature by screen printing. Ink of composition 2 is used on the discoloring pattern layer 2, to form the yellow color second temperature sensing discoloring pattern layer 2 at an ordinary temperature dried. Next by using ink of composition 3 so as to cover each pattern layer 2, a foaming ink layer is formed by a spray coat method. This foaming ink layer is dried, hardening and foaming, to obtain a transparent heat insulating layer 3, and the cooking device upper plate 1, having a green color temperature sensing discoloring pattern at an ordinary temperature, is completed. Then by visually recognizing a change of color of the pattern layer 2, a surface temperature of the cooking device upper plate 1 can be grasped for whether or not its surface temperature is 40 deg.C or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an upper plate for an induction heating cooker having a temperature-sensitive discoloration pattern in which the pattern on the surface of the upper plate is discolored by the temperature change of the object to be heated.

[0002]

2. Description of the Related Art Conventionally, a container 6, which is an object to be heated, is placed on the surface of an induction heating cooker upper plate 1 having a magnetic force generating coil 5 disposed on the back side, and an eddy current 8 is applied to the container 6 by the action of magnetic force lines 7.
There is an induction heating cooker that generates heat and heats the container 6 itself (see FIG. 4). Since the induction heating cooker does not heat the container by using fire, it has advantages such as not worrying about fire and keeping the air in the room clean.

[0003]

However, the prior art has the following problems. (1) The upper plate for an induction heating cooker conducts the heat generated from the object to be heated even if it does not generate heat by itself, so it has a considerable amount of heat immediately after cooking, and you can inadvertently put your hand on it. There is a risk of burns. Therefore, as a measure to prevent accidents, cautions are given to the user by writing cautions on the product itself and in the catalog, but in reality it is difficult to tell whether it is hot or not from the appearance, so there is a risk of burns. The sex was constant.

(2) Even if the magnetic force is the same, the amount of heat generated by the induction-heated object varies depending on the material and thickness of the induction-heated object. In that case, it is difficult to grasp the actual heat generation temperature of the induction-heated object, and the temperature cannot be controlled.

Therefore, an object of the present invention is to solve the above problems and to provide an upper plate for an induction heating cooker having a low risk of burns or having a temperature-sensitive discoloration pattern capable of controlling temperature. To do.

[0006]

In order to achieve the above object, the upper plate for an induction heating cooker having a temperature-sensitive discoloration pattern of the present invention is provided on the surface of the upper plate for an induction heating cooker on which the object to be heated is placed. At least one reversible temperature-sensitive color change pattern layer having a color change temperature of 40 ° C. or higher was formed, and a transparent heat insulating layer was formed on the temperature-sensitive color change pattern layer.

The induction heating cooker upper plate having the temperature-sensitive discoloration pattern of the present invention has a transparent heat insulating base material disposed on the surface of the induction heating cooker upper plate on which the object to be heated is placed. At least one reversible temperature-sensitive color change pattern layer having a color change temperature of 40 ° C. or higher may be formed between the upper plate and the transparent heat insulating substrate.

The induction heating cooker upper plate having the temperature-sensitive discoloration pattern of the present invention is made of a transparent heat insulating material for the induction heating cooker upper plate, and is provided on the surface opposite to the surface on which the induction heating object is placed. At least one reversible temperature-sensitive color change pattern layer having a color change temperature of 40 ° C. or higher may be formed.

Hereinafter, the upper plate for an induction heating cooker having the temperature-sensitive discoloration pattern of the present invention will be described in more detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of an upper plate for an induction heating cooker having a temperature-sensitive color changing pattern according to the present invention, and FIGS. 2 and 3 are induction heating cooking having a temperature-sensitive color changing pattern according to the present invention. It is sectional drawing which shows the other Example of a dexterity upper plate. 1 is an induction heating cooker upper plate, 2 is a temperature-sensitive discoloration pattern layer, 3 is a transparent heat insulating layer, and 4 is a transparent heat insulating substrate.

As the material of the upper plate 1 for induction heating cooker,
Usually, ceramics such as silicon carbide and silicon nitride, and engineering plastics having excellent heat resistance and a low coefficient of thermal expansion are used.

The temperature-sensitive color change pattern layer 2 is a layer in which the color of the pattern reversibly changes due to temperature change, and is partially or wholly provided on the surface of the induction heating cooker upper plate 1 on which the object to be induction-heated is placed. .

The temperature-sensitive discoloration pattern layer 2 is limited to one having a discoloration temperature of 40 ° C. or higher so as not to be discolored by a slight amount of residual heat generated in a circuit device inside the induction heating cooker or the temperature. . To prevent burns, the discoloration temperature should be 90%.
At least one thermosensitive discoloration pattern layer 2 having a temperature of not more than 0 ° C. is required. If the surface temperature of the induction heating cooker top plate 1 exceeds 90 ° C., there is a risk of burns if the user touches it inadvertently.

As the material of the temperature-sensitive color changing pattern layer 2, a resin binder containing a reversible temperature-sensitive color changing material is used. The reversible temperature-sensitive color change material is, for example, a microcapsule of two components of an electron-donating compound and an electron-accepting compound, and a crystal state in which the electron-donating compound and the electron-accepting compound interact with each other. In some cases, the color is colored, and when heated, the electron-accepting compound dissolves to lose the exchange of electrons with each other and become colorless. Other reversible temperature-sensitive color change agents are those whose main pigment is a metal complex salt of silver, mercury, copper, etc., whose color changes due to crystal type transition (physical change), and which have multiple color change temperatures. There are some that change color continuously in response to temperature changes (cholesteric liquid crystal). Various resins can be used as the resin binder, but it is necessary that the temperature-sensitive discoloration pattern layer 2 is firmly adhered to the upper plate 1 for the induction heating cooker, and that it has impact resistance and abrasion resistance. It is preferable to use a thermosetting resin such as an acrylic resin, a melamine resin, an epoxy resin, a urethane resin, or a phenol resin, or an ultraviolet curable resin such as a cyanoacrylate.

As the method for forming the temperature-sensitive discoloration pattern layer 2, there are usual printing methods such as gravure printing and screen printing, transfer methods, and coating methods such as roll coating, spin coating and spray coating. Since microcapsules have weak resistance to alcoholic solvents, it is preferable to use a nonpolar solvent for forming the temperature-sensitive color change pattern layer 2 containing the microcapsule type reversible temperature-sensitive color change material.

The temperature-sensitive discoloration pattern layer 2 may be provided with two or more layers having different discoloration temperatures. For example, the second temperature sensitive color changing pattern layer may be formed on the first temperature sensitive color changing pattern layer, or the first temperature sensitive color changing pattern layer and the second temperature sensitive color changing pattern layer may be formed in parallel. May be. By forming a plurality of temperature-sensitive color changing pattern layers 2 having slightly different color changing temperatures on the surface of the induction heating cooker upper plate 1, it is possible to visually grasp the change in the heat generation temperature of the induction-heated object. Then, the magnetic force control switch can be raised or lowered based on the change in the heat generation temperature. In addition, you may provide the temperature-sensitive discoloration pattern layer 2 of two or more different colors. In this case, the discoloration temperature of the temperature-sensitive discoloration pattern layer 2 may be the same or different.

The transparent heat insulating layer 3 is a layer for partially blocking the heat from the object to be induction-heated, and is formed so as to cover the temperature-sensitive discoloration pattern layer 2 (see FIG. 1). As the transparent heat insulating layer 3,
For example, there is a foamed ink layer that exhibits a heat insulating effect by the air in the small holes. As a method of forming the transparent heat insulating layer 3,
There are usual printing methods such as gravure printing and screen printing, transfer methods, and coating methods such as roll coating, spin coating, and spray coating. When the foamed ink layer is used as the transparent heat insulating layer 3, the ink layer is formed by the above method using the ink in which the gas-containing microcapsules are dispersed in the resin binder, and then the microcapsules are destroyed by heating. To foam.

A transparent heat insulating base material 4 may be used in place of the transparent heat insulating layer 3 in order to partially block heat from the induction heating object. That is, as shown in FIG. 2, the transparent heat insulating substrate 4 is provided on the surface of the induction heating cooker upper plate 1 on which the object to be heated is placed.
And the temperature sensitive color change pattern layer 2 is formed between the upper plate 1 for induction heating cookers and the transparent heat insulating substrate 4. The temperature-sensitive color change pattern layer 2 may be formed on the surface of the induction heating cooker upper plate 1 on which the object to be heated is placed by a printing method, a transfer method, or a coating method, or the transparent heat insulating substrate 4 may be formed. It may be formed on the surface facing the upper plate 1 for the induction heating cooker. As the transparent heat insulating substrate 4, glass, Y ₂ O ₃ , MgO, LiAl ₅ O ₈ , Sc ₂ O ₃ , MgAl ₄ O ₇ , ThO ₂ , Al ₂ O.
_In addition to a plate made of transparent ceramic such as ₃ , a film made of heat-resistant plastic such as polysulfone, polyether sulfone, polyamide, polyetherimide, or nylon may be used. Moreover, you may form the transparent heat insulation layer 3 on the surface of the transparent heat insulation base material 4 as needed.

The induction heating cooker upper plate 1 may be made of a transparent heat insulating material such as transparent ceramic, and the temperature-sensitive discoloration pattern layer 2 may be formed on the surface opposite to the surface on which the object to be heated is placed. (See Figure 3).

[0020]

The upper plate for an induction heating cooker having the temperature-sensitive discoloration pattern of the present invention has the following actions since it has the above-mentioned structure.

That is, the surface temperature of the upper plate for the induction heating cooker changes in accordance with the change in the heat generation temperature of the induction-heated object, and when the surface temperature reaches the color change temperature of each temperature-sensitive color change pattern layer, the temperature-sensitive color change pattern The layers discolor. Therefore, by visually observing the color change of the temperature-sensitive color change pattern layer, the surface temperature of the induction heating cooker upper plate, and thus the heat generation temperature of the induction-heated object, can be grasped.

Further, by interposing a transparent heat insulating layer or a transparent heat insulating base material for reducing heat transfer between the induction heating object and the temperature sensitive color changing pattern layer, the induction heating object is exposed to the temperature sensitive color changing pattern. The temperature of the heat applied to the layer is lower than the heat generation temperature of the induction-heated object.

[0023]

【Example】

Example 1 First, a plate made of silicon nitride was used as an upper plate for an induction heating cooker, and an ink of the following composition 1 was used on the surface of the upper plate for an induction heating cooker to screen a blue first thermosensitive color changing pattern layer at room temperature. It was formed by printing. Then, a yellow second temperature-sensitive color changing pattern layer was formed on the first temperature-sensitive color changing pattern layer by screen printing using an ink having the following composition 2 and dried at 150 ° C. for 5 minutes. Finally, a foam ink layer was formed by a spray coating method using the ink of the following composition 3 so as to cover each of the above-mentioned temperature-sensitive color changing pattern layers, and the foam ink layer was thermally cured by drying at 150 ° C for 30 minutes. And it foamed and it was set as a transparent heat insulation layer, and the upper board for induction heating cookers which has a green thermosensitive color change pattern at normal temperature was completed.

Composition 1 Binder Seiko Advance Co., Ltd. 1300 60 parts (acrylic resin) Temperature-sensitive color change material Three Tech Davis Co., Ltd. KTM-60 25 parts (microcapsule type, reversible change from blue to colorless when heated above 60 ° C.) ) Diluting solvent Ethyl carbitol acetate 15 parts Composition 2 Binder Seiko Advance Co., Ltd. 1300 60 parts (Acrylic resin) Temperature-sensitive color change material Three Tech Davis Co., Ltd. KTM-40 25 parts (Microcapsule type, when heated above 40 ° C) Reversible change from yellow to colorless) Diluting solvent ethyl carbitol acetate 15 parts Composition 3 Binder Okuno Pharmaceutical Co., Ltd. CRM ink (silicon oxide) 70 parts Gas-containing microcapsules 2 parts Diluting solvent ethyl carbitol acetate 28 parts

When the upper plate for an induction heating cooker thus obtained was used for heating in an induction heating cooker, the green pattern on the surface of the upper plate changed to blue at 40 ° C and further at 60 ° C. It turned white.

Example 2 First, a plate made of silicon nitride was used as the upper plate for an induction heating cooker, and an ink having the following composition 4 was used on the entire surface of the upper plate for the induction heating cooker to produce a red thermosensitive color change pattern layer at room temperature. Was formed by screen printing and dried at 150 ° C. for 5 minutes. Next, an Al ₂ O ₃ plate was placed on the temperature-sensitive color changing pattern layer as a transparent heat insulating substrate to complete an induction heating cooker upper plate having a red temperature-sensitive color changing pattern at room temperature.

Composition 4 Binder Seiko Advance Co., Ltd. 1300 60 parts (acrylic resin) Temperature-sensitive color change material Dainichi Seika Co., Ltd. PR-70 25 parts (metal type, reversible from red to black-purple when heated above 70 ° C.) Change) Diluting solvent Ethyl carbitol acetate 15 parts

When the upper plate for an induction heating cooker thus obtained was used for heating in an induction heating cooker, 70
The entire surface of the upper plate changed from red to black-purple at ℃.

Example 3 First, a plastics film made of polyamide was used as a transparent heat insulating substrate, and a red first thermosensitive color changing pattern layer was screened on the back surface of the transparent heat insulating substrate at room temperature using an ink having the following composition 5. It was formed by printing. Next, a colorless second temperature-sensitive color changing pattern layer is formed by screen printing in parallel with the first temperature-sensitive color changing pattern layer at a normal temperature using an ink having the following composition 6:
It was dried at 0 ° C. for 5 minutes. Finally, a plate made of silicon carbide is used as the upper plate for the induction heating cooker, and the transparent heat-insulating base material is placed on the surface on which the object to be heated is placed, and the induction heating cooker has a red thermosensitive discoloration pattern at room temperature. Completed the board.

Composition 5 Binder Seiko Advance Co., Ltd. 1300 60 parts (acrylic resin) Thermochromic material Dainichi Seika Co., Ltd. PR-70 25 parts (metal type, reversible from red to black-purple when heated above 70 ° C.) Change) Diluting solvent Ethyl carbitol acetate 15 parts Composition 6 Binder Polyvinyl alcohol resin 10 parts Temperature-sensing color change material Merck Co., Ltd. chiral nematic liquid crystal 50 parts (liquid crystal type, reversible change from colorless to red when heated above 50 ° C, 55 ° C) Reversible change from red to green when heated above, reversible change from green to blue when heated above 60 ° C, reversible change from blue to colorless when heated above 70 ° C) Diluting solvent Water 40 parts

When the upper plate for the induction heating cooker thus obtained was used for heating in the induction heating cooker, the second temperature-sensitive color changing pattern layer was formed in parallel with the red color of the first temperature-sensitive color changing pattern layer.
It newly appears on the surface of the upper plate as red at 50 ° C, and the pattern of the second temperature-sensitive discoloration pattern layer changes to green at 55 ° C and blue at 60 ° C.
It disappeared again at ℃. At 70 ° C, the blue pattern disappeared, and at the same time, the first temperature-sensitive discoloration pattern layer, which remained red at room temperature, changed to black-purple.

Example 4 First, a glass plate which is a transparent heat insulating material was used as the upper plate for the induction heating cooker, and the following composition 7 was formed on the entire surface of the upper plate for the induction heating cooker opposite to the surface on which the object to be heated for induction was placed. A red temperature-sensitive color changing pattern layer was formed by screen printing using the above ink and dried at 150 ° C. for 5 minutes to complete an induction heating cooker upper plate having a red temperature changing color pattern at room temperature.

Composition 7 Binder Seiko Advance Co., Ltd. 1300 60 parts (acrylic resin) Temperature-sensitive color change material Dainichi Seika Co., Ltd. PR-70 25 parts (metal type, reversible from red to black-purple when heated above 70 ° C.) Change) Diluting solvent Ethyl carbitol acetate 15 parts

The induction heating cooker upper plate thus obtained was used for heating in an induction heating cooker.
The entire surface of the upper plate changed from red to black-purple at ℃.

[0035]

Since the upper plate for an induction heating cooker having the temperature-sensitive color change pattern of the present invention has the above-mentioned constitution and action,
It has the following effects.

(1) Since the surface temperature of the upper plate for induction heating cookers can be grasped by visually recognizing the color change of the temperature-sensitive color changing pattern layer, carelessly touching the upper plate for induction heating cookers with heat. There is no risk of getting burned by putting on.

(2) By visually recognizing the color change of one temperature sensitive color changing pattern layer having a plurality of color changing temperatures or a plurality of temperature sensitive color changing pattern layers having different color changing temperatures, the heat generation temperature of the induction-heated object can be grasped. As a result, it is possible to perform fine temperature control.

(3) By suppressing the temperature of heat applied to the temperature-sensitive discoloration pattern layer from the object to be heated to a lower temperature than the heat generation temperature of the object to be heated, no matter how many times cooking is performed, Degradation of the temperature-sensitive color changing pattern layer such that the color of the temperature-sensitive color changing material does not change at the color changing temperature or the binder is blackened does not occur.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of an induction heating cooker upper plate having a temperature-sensitive color change pattern according to the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the upper plate for an induction heating cooker having a temperature-sensitive color change pattern according to the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the upper plate for an induction heating cooker having a temperature-sensitive color change pattern according to the present invention.

FIG. 4 is an explanatory view of the principle of the induction heating cooker.

[Explanation of symbols]

 1 Upper plate for induction heating cooker 2 Temperature-sensitive discoloration pattern layer 3 Transparent heat insulating layer 4 Transparent heat insulating base material 5 Magnetic force generating coil 6 Container 7 Magnetic force line 8 Eddy current

Claims (3)

[Claims] 1. At least one reversible temperature-sensitive color change pattern layer having a color change temperature of 40 ° C. or higher is formed on the surface of the induction heating cooker on which the object to be heated is placed, and the temperature-sensitive color change pattern layer is transparent. An upper plate for an induction heating cooker having a temperature-sensitive discoloration pattern, characterized in that a heat insulating layer is formed. 2. A transparent heat insulating base material is arranged on a surface of the induction heating cooker upper plate on which the object to be heated is placed, and the discoloration temperature is 40 ° C. or higher between the induction heating cooker upper plate and the transparent heat insulating base material. At least one reversible temperature-sensitive color change pattern layer is formed, and the upper plate for an induction heating cooker has a temperature-sensitive color change pattern. 3. The induction heating cooker upper plate is made of a transparent heat insulating material, and at least a reversible temperature-sensitive discoloration pattern layer having a discoloration temperature of 40 ° C. or more is provided on the surface opposite to the surface on which the object to be heated is placed. An upper plate for an induction heating cooker having a temperature-sensitive discoloration pattern, which is formed by one layer.