JP2011192535A - Top plate for electromagnetic heating cooker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a top plate for an electromagnetic heating cooker which is excellent in heat resistance and constituted by forming a heat resistant resin layer on a glass substrate. <P>SOLUTION: The top plate 1 for an electromagnetic heating cooker includes a glass substrate 2 and a heat resistant resin layer 4. The heat resistant resin layer 4 is formed on the glass substrate 2. The heat resistant resin layer 4 contains inorganic pigment powder and silicone resin. The content of the inorganic pigment powder in the heat resistant resin layer 4 is in a range of 55 to 75 mass%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a top plate for an electromagnetic heating cooker.

  As a heating device of an electric cooker, an infrared heating device such as a radiant heater, a halogen heater known as a high output type, or an electromagnetic heating device such as an induction heater (IH) is used.

  Conventionally, as a top plate of a cooker equipped with an infrared heating device, a dark-colored crystallized glass plate that blocks visible light and transmits infrared light has been widely used. By using a dark-crystallized glass plate as the top plate, the members placed on the back side of the top plate can be concealed to enhance aesthetics, and the anti-glare of the infrared heating device that emits strong visible light It is because it can plan.

  In addition, since the cooker provided with the infrared heating apparatus can visually recognize the red-heated heater part through the dark crystallized glass plate, there is no need to provide a mechanism for displaying that heating is in progress.

  On the other hand, unlike an infrared heating device, a cooking device equipped with an electromagnetic heating device (hereinafter referred to as “IH cooking device”) does not generate visible light even during heat generation. For this reason, the IH cooker needs to be provided with a mechanism for indicating that heating is in progress. Conventionally, for example, a light-emitting diode is used as the display mechanism.

  However, the light from the light emitting diode is weaker than the light from the infrared heating device. For this reason, for example, when the above-described dark crystallized glass plate is used as the top plate of the IH cooker, there arises a problem that the visibility of the light-emitting diode disposed on the back side of the top plate is deteriorated.

  In view of such a problem, for example, the following Patent Document 1 proposes to use a low expansion crystallized glass having a light shielding layer formed on the surface as a top plate. Further, Patent Document 1 describes that by making the light shielding layer porous, it is possible to suppress the occurrence of cracks in the light shielding layer due to the difference in thermal expansion coefficient between the light shielding layer and the low expansion crystallized glass. ing.

  However, when a porous light-shielding layer is employed, there is a problem that adhesion marks of a temperature sensor (thermocouple) attached to the electromagnetic heating portion on the back surface of the top plate are conspicuous and are not preferable in appearance.

  In order to solve this problem, in Patent Document 2 below, as a top plate for an IH cooker, a porous light-shielding film is formed on the surface of a low expansion crystallized glass plate, and at least an electromagnetic heating portion of the light-shielding film. A top plate having a heat-resistant resin layer formed thereon has been proposed.

  Further, as described above, the low-expansion crystallized glass plate and the light-shielding film usually have different thermal expansion coefficients, so that the light-shielding film tends to crack, so that a sufficiently thick light-shielding film cannot be formed. In some cases, it may not be possible to obtain sufficient concealability with only the coating. In such a case, a heat resistant resin layer for supplementing the light shielding property may be formed on the light shielding film.

Japanese Patent Laid-Open No. 10-273342 JP 2003-338360 A

  By the way, in an IH cooker, a cooker such as a pan is directly heated by an electromagnetic heating device. For this reason, the top plate is not directly heated by the electromagnetic heating device. Moreover, since the cooking device is heated in a state where an object to be heated that normally contains moisture is placed, the temperature of the cooking device does not become so high. Therefore, normally, the temperature of the top plate does not rise so high.

  However, when the cooking device is heated in a state where there is no food to be cooked inside, the cooking device becomes high temperature, and accordingly, the temperature of the top plate becomes high temperature of 400 ° C. or more. There is also. Then, the heat resistant resin layer may be thermally deteriorated and discolored. When the heat resistant resin layer changes color, the color change of the heat resistant resin layer is visually recognized from the use surface side, and there is a problem that the appearance is deteriorated.

  The present invention has been made to solve the above-mentioned problems of the prior art, and is a top plate for an electromagnetic heating cooker in which a heat-resistant resin layer is formed on a glass substrate, and is heat resistant. An object is to provide an excellent top plate for an electromagnetic heating cooker.

  The top plate for an electromagnetic heating cooker according to the present invention includes a glass substrate and a heat resistant resin layer. The heat resistant resin layer is formed on the glass substrate. The heat resistant resin layer includes an inorganic pigment powder and a silicone resin. In this invention, content of the inorganic pigment powder in a heat resistant resin layer exists in the range of 55 mass%-75 mass%. For this reason, for example, even when the top plate is at a high temperature of 400 ° C. or higher, the heat-resistant resin layer is not easily discolored. Therefore, a top plate for an electromagnetic heating cooker having high heat resistance can be realized.

  In this invention, it is preferable that content of the inorganic pigment powder in a heat resistant resin layer exists in the range of 57 mass%-70 mass%.

  In the present invention, the “glass substrate” includes a crystallized glass substrate.

  In the present invention, the top plate for an electromagnetic heating cooker may further include an inorganic light shielding layer formed between the glass substrate and the heat resistant resin layer. When the top plate for an electromagnetic heating cooker having such a configuration is used, the members disposed inside the electromagnetic heating cooker can be more effectively concealed, and the aesthetics of the electromagnetic heating cooker can be further enhanced.

  The “inorganic light shielding layer” is a layer that absorbs or reflects at least part of incident light. In the present invention, the “inorganic light shielding layer” is not limited to one that absorbs or reflects all incident light.

  In the present invention, the silicone resin contained in the heat resistant resin layer is preferably a silicone resin in which a functional group directly bonded to a silicon atom is at least one of a methyl group and a phenyl group. In this case, discoloration of the heat-resistant resin layer when the top plate becomes high temperature can be more effectively suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, it is a top plate for electromagnetic heating cookers by which the inorganic light shielding layer and the heat resistant resin layer are formed on the glass substrate, Comprising: It provides the top plate for electromagnetic heating cookers excellent in heat resistance. it can.

It is a schematic sectional drawing of the top plate for electromagnetic heating cookers which concerns on one Embodiment which implemented this invention.

  FIG. 1 is a schematic cross-sectional view of a top plate for an electromagnetic heating cooker according to an embodiment of the present invention.

  Hereinafter, a preferred embodiment in which the present invention is implemented is exemplified by a top plate 1 for an electromagnetic heating cooker (hereinafter, “the top plate 1 for an electromagnetic heating cooker” is simply referred to as “top plate 1”) shown in FIG. I will explain. However, the top plate 1 is merely an example. The top plate for an electromagnetic heating cooker according to the present invention is not limited to the top plate 1 at all.

  As shown in FIG. 1, the top plate 1 includes a glass substrate 2. The glass substrate 2 transmits at least part of light having a wavelength of 450 nm to 700 nm. The glass substrate 2 may be colored and transparent, but is preferably colorless and transparent from the viewpoint of enhancing the aesthetics of the top plate 1. In addition, being colorless and transparent means that the light transmittance in the visible wavelength region at a wavelength of 450 nm to 700 nm is 75% or more.

The top plate 1 is repeatedly heated and cooled. For this reason, it is preferable that the glass substrate 2 has high heat resistance and a low thermal expansion coefficient. Specifically, the softening temperature of the glass substrate 2 is preferably 700 ° C. or higher, and more preferably 750 ° C. or higher. The average linear thermal expansion coefficient at 30 ° C. to 750 ° C. of glass substrate 2 is preferably in the range of ^{-10 × 10 -7 / ℃ ~ +} 30 × 10 -7 / ℃, -10 × 10 -7 It is more preferable to be within the range of / ° C to + 20 × 10 ⁻⁷ / ° C. For this reason, the glass substrate 2 preferably has a high glass transition temperature and is made of low expansion glass or low expansion crystallized glass. As a specific example of the low-expansion crystallized glass, for example, Neoceram N-0 manufactured by Nippon Electric Glass Co., Ltd. can be mentioned.

  In this embodiment, the inorganic light shielding layer 3 is formed on the back surface 2a on the opposite side of the cooking surface 2b of the glass substrate 2. A heat resistant resin layer 4 is formed on the inorganic light shielding layer 3. In the present embodiment, the heat resistant resin layer 4 is formed on the entire back surface 2 a of the glass substrate 2.

The inorganic light shielding layer 3 is not particularly limited as long as it is made of an inorganic material and has a low visible light transmittance. The inorganic light shielding layer 3 can be formed of a metal film such as titanium, for example. Moreover, the inorganic light shielding layer 3 can also be formed by the layer containing an inorganic pigment and glass. In this case, for example, a Cu—Cr—Mn black inorganic pigment can be used as the inorganic pigment. Moreover, as glass, for example, B ₂ O ₃ —SiO ₂ glass powder can be used.

  The inorganic light-shielding film 3 may be a porous film or a solid film having substantially no voids.

  The thickness of the inorganic light shielding layer 3 is not particularly limited. The thickness of the inorganic light shielding layer 3 can be appropriately set according to, for example, the light transmittance of the inorganic light shielding layer 3, the mechanical strength of the inorganic light shielding layer 3, the thermal expansion coefficient, and the like. The inorganic light shielding layer 3 usually has a different thermal expansion coefficient from that of the glass substrate 2. For this reason, the inorganic light shielding layer 3 may be damaged by repeated heating and cooling. From the viewpoint of suppressing this damage, the inorganic light shielding layer 3 is preferably thin. The thickness of the inorganic light shielding layer 3 is preferably in the range of 1 μm to 15 μm, and more preferably in the range of 3 μm to 10 μm.

  The formation method of the inorganic light shielding layer 3 is not particularly limited. The inorganic light shielding layer 3 can be formed by the following method, for example.

  First, a solvent is added to a mixed powder of inorganic pigment powder and glass powder to form a paste. The paste is applied onto the glass substrate 2 using a screen printing method or the like, and dried. Then, the inorganic light shielding layer 3 can be formed by baking. The firing temperature and firing time can be appropriately set according to the composition of the glass powder used. The firing temperature can be, for example, about 200 ° C. to 400 ° C. The firing time can be, for example, about 10 minutes to 1 hour.

  Moreover, when the inorganic light shielding layer 3 consists of a metal film, it can form by sputtering method, CVD method, etc.

  The heat resistant resin layer 4 contains an inorganic pigment powder and a silicone resin. In the heat resistant resin layer 4, the inorganic pigment powder is dispersed in the silicone resin. In the present embodiment, the content of the inorganic pigment powder in the heat resistant resin layer 4 is in the range of 55% by mass to 75% by mass.

The inorganic pigment powder contained in the heat resistant resin layer 4 is not particularly limited as long as it is a colored inorganic substance. The inorganic pigment powder is, for example, white pigment powder such as TiO ₂ powder, ZrO ₂ powder, ZrSiO ₄ powder, blue or green inorganic pigment powder containing Co, green inorganic pigment powder containing Co, Ti—Sb—Cr. Series, Ti-Ni yellow inorganic pigment powder, Co-Si red inorganic pigment powder, brown inorganic pigment powder containing Fe, black inorganic pigment powder containing Cu, and the like.

Specific examples of the blue inorganic pigment powder containing Co include, for example, Co—Al-based and Co—Al—Ti-based inorganic pigment powders. Specific examples of the Co—Al based inorganic pigment powder include CoAl ₂ O ₄ powder. Specific examples of the Co—Al—Ti inorganic pigment powder include CoAl ₂ O ₄ : TiO ₂ : Li ₂ O powder.

Specific examples of the green inorganic pigment powder containing Co include, for example, Co-Al-Cr-based and Co-Ni-Ti-Zn-based inorganic pigment powders. Specific examples of the Co—Al—Cr inorganic pigment powder include Co (Al, Cr) ₂ O ₄ powder. Specific examples of the Co—Ni—Ti—Zn inorganic pigment powder include (Co, Ni, Zn) ₂ TiO ₄ powder and the like.

Specific examples of the brown inorganic pigment powder containing Fe include, for example, Fe-Zn inorganic pigment powder. Specific examples of the Fe—Zn inorganic pigment powder include (Zn, Fe) Fe ₂ O ₄ powder.

Specific examples of the black inorganic pigment powder containing Cu include, for example, a Cu—Cr based inorganic pigment powder. Specific examples of the Cu-Cr-based inorganic pigment powder include Cu (Cr, Mn) ₂ O ₄ powder.

  These inorganic pigment powders can be used alone or in combination.

  The silicone resin contained in the heat resistant resin layer 4 is preferably one having high heat resistance. The silicone resin contained in the heat-resistant resin layer 4 is preferably a silicone resin in which the functional group directly bonded to the silicon atom is at least one of a methyl group and a phenyl group, and the functional group directly bonded to the silicon atom is a methyl group. More preferably, it is a silicone resin.

  The thickness of the heat resistant resin layer 4 is not particularly limited. The thickness of the heat resistant resin layer 4 can be appropriately set according to the light transmittance of the heat resistant resin layer 4 and the like. The thickness of the heat resistant resin layer 4 can be, for example, about 1 μm to 15 μm.

  The method for forming the heat resistant resin layer 4 is not particularly limited. The heat-resistant resin layer 4 is formed by, for example, applying a silicone resin in which inorganic pigment powder is dispersed on the inorganic light-shielding layer 3 by using a screen printing method, for example, at a temperature of about 50 ° C. to 100 ° C. for 10 minutes to It can be formed by drying for about 1 hour. Further, depending on the composition of the heat-resistant resin layer 4, it may be preferable to perform baking after drying.

  The application speed and viscosity of the silicone resin in which the inorganic pigment powder is dispersed need to be set as appropriate according to the amount of the inorganic pigment powder contained in the heat resistant resin layer 4. For example, when the content of the inorganic pigment powder in the heat resistant resin layer 4 is large, it is preferable to lower the viscosity of the silicone resin and slow down the application speed of the silicone resin.

  As described above, in the present embodiment, the content of the inorganic pigment powder in the heat resistant resin layer 4 is in the range of 55% by mass to 75% by mass. For this reason, as can be seen in the following embodiments, for example, even when the top plate 1 is at a high temperature of 400 ° C. or higher, the heat-resistant resin layer 4 is not easily discolored. Therefore, the top plate 1 having high heat resistance can be realized. If the content of the inorganic pigment powder in the heat resistant resin layer 4 is too small, the discoloration of the heat resistant resin layer 4 when the top plate 1 becomes high temperature cannot be sufficiently suppressed. On the other hand, when there is too much content of the inorganic pigment powder in the heat resistant resin layer 4, the adhesiveness with respect to the inorganic light shielding layer 3 of the heat resistant resin layer 4 will fall, and the heat resistant resin layer 4 will peel easily.

  Moreover, since the heat resistant resin layer 4 has fluidity until it is dried, when the heat resistant resin layer 4 is provided as in this embodiment, the back surface of the top plate 1 is flattened. For this reason, the top plate 1 more excellent in aesthetics can be realized.

  In the present embodiment, the inorganic light shielding layer 3 is provided together with the heat resistant resin layer 4. For this reason, when it sees from the cooking surface 2b side, the member arrange | positioned inside the electromagnetic heating cooking appliance can be concealed more effectively, and the aesthetics of an electromagnetic heating cooking appliance can be improved further.

  In the present embodiment, the silicone resin contained in the heat resistant resin layer 4 is a silicone resin in which the functional group directly bonded to the silicon atom is at least one of a methyl group and a phenyl group. For this reason, discoloration of the heat-resistant resin layer 4 at high temperatures can be more effectively suppressed. The silicone resin contained in the heat resistant resin layer 4 is more preferably a silicone resin in which the functional group directly bonded to the silicon atom is a methyl group.

  In the above embodiment, the case where the inorganic light shielding layer 3 is provided between the glass substrate 2 and the heat resistant resin layer 4 has been described. However, the present invention is not limited to this configuration. For example, an inorganic light shielding layer may be provided directly on the glass substrate.

  Moreover, in the said embodiment, the case where the heat resistant resin layer 4 was formed on the whole back surface 2a of the glass substrate 2 was demonstrated. However, the present invention is not limited to this configuration. The heat resistant resin layer 4 may be formed on a part of the back surface 2a of the glass substrate 2, for example. For example, the heat resistant resin layer 4 may be provided only on the electromagnetic heating portion of the top plate 1. Further, for example, when the inorganic light-shielding layer 3 is formed of a porous film, at least a part below the adhesive part of a temperature sensor (thermocouple) attached to the electromagnetic heating part on the back surface of the top plate 1 has a heat resistant resin. Layer 4 may be provided. In that case, adhesion marks of the temperature sensor can be made inconspicuous, and the appearance of the top plate 1 can be improved.

  In the said embodiment, the example in which the film | membrane is not formed on the cooking surface 2b of the glass substrate 2 was demonstrated. However, the present invention is not limited to this configuration. For example, a decorative coating may be formed on the cooking surface 2b as necessary for improving design properties, displaying the heater position, and the like.

  Further, a further film may be formed on the back surface 2 a side of the glass substrate 2. For example, a protective layer or the like of the heat resistant resin layer 4 may be formed on the heat resistant resin layer 4, or an adhesion layer or the like may be formed between the heat resistant resin layer 4 and the inorganic light shielding layer 3. Good.

(Example)
Hereinafter, the present invention will be described in more detail based on examples. However, the following examples are merely illustrative. The present invention is not limited to the following examples.

First, an inorganic pigment powder Cu-Cr-Mn type _black, B ₂ O 3 -SiO ₂ based glass powder _(SiO 2: 63 _{wt%, B 2} O 3: 19 wt%) of 3: 7 weight ratio of Then, a paste was prepared by adding a resin and an organic solvent. Next, this paste was applied to a transparent crystallized glass plate N-0 (average linear thermal expansion coefficient at 30 ° C. to 750 ° C .: −4 × 10 ⁻⁷ / ° C.) made by Nippon Electric Glass Co., Ltd., with a film thickness of 4 μm. It was screen printed so that Subsequently, the applied paste was dried at 150 ° C. for 5 minutes and then baked at 850 ° C. for 30 minutes to form an inorganic light shielding layer.

  Next, the inorganic pigment powder and the silicone resin are mixed so that the mass ratio is 6.7: 3.3 (that is, the content of the inorganic pigment powder in the heat-resistant resin layer is 67 mass%), and the organic solvent is added. The paste was prepared by adding. This paste is screen-printed on the entire inorganic light-shielding layer so as to have a thickness of 4 μm, dried at 150 ° C. for 5 minutes, and then baked at 300 ° C. for 30 minutes to form a heat-resistant resin layer. To complete the top plate. As the inorganic pigment, black 42-701A (manufactured by Nippon Fellow Co., Ltd.) was used.

  The produced top plate was incorporated in an electromagnetic heating device, and the pan was aired to hold the top plate at 500 ° C. for 10 minutes (air-cooking test). Then, the discoloration of the heat resistant resin layer was visually observed from the cooking surface side of the top plate. In this example, no discoloration of the heat resistant resin layer could be confirmed.

(Comparative example)
A top plate was prepared in the same manner as in the above example except that the weight ratio of the inorganic pigment powder to the silicone resin was 4: 6, and the same blanking test was performed. As a result, in this comparative example, discoloration of the heat resistant resin layer was confirmed.

  From the above results, according to the present invention, by setting the content of the inorganic pigment powder in the heat resistant resin layer within the range of 55% by mass to 75% by mass, the heat resistant resin layer is not easily discolored even at high temperatures, and is high. It turns out that the top plate for electromagnetic heating cookers which has heat resistance is realizable.

DESCRIPTION OF SYMBOLS 1 ... Top plate 2 for electromagnetic heating cookers ... Glass substrate 3 ... Inorganic light shielding layer 4 ... Heat-resistant resin layer

Claims (3)

A glass substrate;
A top plate for an electromagnetic heating cooker comprising a heat resistant resin layer formed on the glass substrate,
The heat resistant resin layer includes an inorganic pigment powder and a silicone resin,
The top plate for an electromagnetic heating cooker, wherein the content of the inorganic pigment powder in the heat-resistant resin layer is within a range of 55 mass% to 75 mass%.   The top plate for an electromagnetic heating cooker according to claim 1, further comprising an inorganic light shielding layer formed between the glass substrate and the heat resistant resin layer.   The top plate for an electromagnetic heating cooker according to claim 1 or 2, wherein the silicone resin is a silicone resin in which a functional group directly bonded to a silicon atom is at least one of a methyl group and a phenyl group.

Images