Heat cooker and method for manufacturing the same

Abstract

To provide a heat cooker that has a high rate of temperature increase and reduced power consumption.SOLUTION: A heat cooker includes wiring that comprises a plating layer and is formed at a ceramic substrate. The heat cooker heats the ceramic substrate by energizing the wiring.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooking utensil and a method for manufacturing the same. [Background technology]

[0002] Hot plates for cooking are widely used in households because they are easy to use. Many conventional hot plates are made up of a plate body and a body case equipped with a rod-shaped heater unit that can be detached. However, such hot plates have a slow heating speed and consume a lot of power. In addition, the combined thickness of the plate body and body case is thick, bulky, and heavy. Furthermore, the large temperature difference between the parts close to the heater unit and the parts far from it makes it easy for uneven cooking and burning to occur.

[0003] Patent Document 1 describes a cooking hot plate that includes a front plate, a film heater disposed on the lower surface of the front plate, and a back plate disposed on the lower surface of the front plate. It is described that the hot plate can be downsized and lightweight, and can also effectively utilize the radiant heat radiated from the film heater, which is a heat source. However, the hot plate has a slow heating rate and consumes a lot of power. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Registered Utility Model No. 3233768 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made to solve the above problems, and has an object to provide a cooking utensil that has a fast temperature rise rate and consumes little power. [Means for solving the problem]

[0006] The above problem is solved by providing a cooking utensil in which wiring made of a plating layer is formed on the surface of a ceramic base material, and the ceramic base material is heated by passing electricity through the wiring. In this case, it is preferable that the plating layer contains Ni, P, and W. It is also preferable that an insulating layer is formed on the surface of the plating layer. It is also preferable that the cooking utensil further includes a housing that houses the ceramic base material on which the wiring is formed and has a power supply device that supplies power to the wiring.

[0007] The above-mentioned problem is also solved by providing a manufacturing method of the cooking utensil for forming the plating layer on the surface of the ceramic base by electroless plating. In this case, it is preferable to roughen a part of the surface of the ceramic base by irradiating the part with a pulse laser, and to form the plating layer on the surface of the part by electroless plating. Effect of the Invention

[0008] The cooking utensil of the present invention has a high temperature rise rate and consumes little power. According to the manufacturing method of the present invention, such a cooking utensil can be easily manufactured. [Brief description of the drawings]

[0009] [Figure 1] 4 is a photograph showing the appearance of the lower surface of a ceramic base on which wiring made of a plating layer is formed in Example 1. [Diagram 2] 2 is a photograph showing the appearance of a cooking utensil in which a ceramic base is provided in a power supply device in Example 1. [Diagram 3] 1 shows thermography images of the upper surface of a ceramic base when a current is passed through wiring in Example 1 and Comparative Example 1. [Figure 4] 1 is a graph in which the temperature (vertical axis) of the upper surface of the ceramic base (part corresponding to the wiring) is plotted against the current-flow time (horizontal axis) in Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The cooking utensil of the present invention has a ceramic base material having a wiring formed of a plating layer on the surface thereof, and the ceramic base material is heated by passing an electric current through the wiring. Such a cooking utensil has a high temperature rise rate and consumes little power.

[0011] Fig. 1 is a photograph showing the appearance of the underside of a ceramic base 2 on which wiring 4 made of a plating layer is formed in Example 1 described below, and Fig. 2 is a photograph showing the appearance of a cooking utensil 1 in which the ceramic base 2 is placed on a power supply device 3 in Example 1. Hereinafter, the cooking utensil 1 of the present invention will be described in detail with reference to these drawings.

[0012] A ceramic substrate 2 is used as a substrate (plate) used in the cooking utensil 1. The ceramic substrate 2 may be a single layer or a multilayer, but is preferably a single layer from the viewpoint of obtaining a high far-infrared effect and from the viewpoint of cost. When the ceramic substrate 2 is a multilayer, at least one layer must be a ceramic layer, and the wiring 4 is formed on the surface of the ceramic layer. As the ceramic substrate 2, a heat-resistant ceramic substrate 2 generally used for cooking utensils, pots, etc. is used, and examples thereof include heat-resistant ceramics and heat-resistant glass. Among these, heat-resistant ceramics are preferred. In terms of further improving heat resistance, the ceramic substrate preferably contains at least one selected from the group consisting of petalite, kaolinite, phlogopite, steatite, and silicon nitride. Among these, the ceramic substrate 2 is preferably a petalite-based ceramic substrate containing petalite.

[0013] The shape of the ceramic base 2 is not particularly limited, and may be any shape suitable for cooking. In terms of improving strength, the thickness of the ceramic base 2 is preferably 0.3 to 30 mm. When the thickness is 0.3 mm or more, the strength of the ceramic base 2 is improved. The thickness is more preferably 0.5 mm or more, and even more preferably 1 mm or more. On the other hand, when the thickness is 30 mm or less, the temperature rise rate of the ceramic base 2 is further increased and power consumption is further reduced. The thickness is more preferably 25 mm or less, and even more preferably 20 mm or less.

[0014] Wiring 4 made of a plating layer is formed on the surface of the ceramic base 2. When electricity is passed through the wiring 4, it generates heat, and food placed on the upper surface of the ceramic base 2 is heated. For safety and durability reasons, the wiring 4 is usually formed on the lower surface of the ceramic base 2. In the present invention, the wiring 4 made of a thin plating layer is formed directly on the surface of the ceramic base 2. Therefore, the ceramic base 2 has high thermal conductivity, and the upper surface of the ceramic base 2 rises in temperature in a short time. Moreover, by forming the wiring 4 from a plating layer, it is possible to make the entire cooking utensil thinner.

[0015] The position where the wiring 4 is formed on the ceramic base 2 is not particularly limited and may be determined according to the position where the food material comes into contact with the ceramic base 2. According to a manufacturing method of the cooking utensil 1 described later, a plating layer of any shape can be formed at any position on the surface of the ceramic base 2. Therefore, the ceramic base can be heated uniformly, so uneven baking and burning are less likely to occur.

[0016] Since the amount of heat generated by passing electricity through the wiring 4 made of the plating layer is proportional to the square of the current and the electrical resistance of the wiring, it is preferable that the plating layer has a certain degree of electrical resistance and excellent heat resistance. From this viewpoint, the plating layer preferably contains at least one metal element selected from the group consisting of Ni, W, Zn, Co, Fe, Pt, Sn, Pb, Ir, Rh, Cr, Bi, Cd, Pd, In, Au, and Mo, more preferably contains at least one metal element selected from the group consisting of Ni and W, and further preferably contains Ni and W. The plating layer may contain other components in addition to the metal elements, such as P and B.

[0017] From the viewpoint of the balance between electrical resistance and heat resistance, it is particularly preferable that the plating layer contains Ni, P, and W. In this case, the total amount of Ni, P, and W in the plating layer is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and even more preferably 98 mass% or more, and it is particularly preferable that the plating layer is substantially composed of only Ni, P, and W. When the plating layer contains Ni, P, and W, the content of P in the plating layer is usually 0.1 to 20 mass parts per 100 mass parts of Ni. Also, the content of W in the plating layer is usually 0.1 to 40 mass parts per 100 mass parts of Ni.

[0018] The thickness of the plating layer is preferably 0.1 to 500 μm. If the thickness of the plating layer is less than 0.1 μm, there is a risk of disconnection. The thickness of the plating layer is more preferably 0.5 μm or more, even more preferably 1 μm or more, and particularly preferably 2 μm or more. On the other hand, if the thickness of the plating layer exceeds 500 μm, there is a risk of an increase in the manufacturing cost of the cooking utensil. The thickness of the plating layer is more preferably 250 μm or less, even more preferably 100 μm or less, particularly preferably 50 μm or less, and most preferably 30 μm or less.

[0019] The width of the wiring 4 made of the plating layer is preferably 0.2 to 50 mm. If the width is less than 0.2 mm, there is a risk of disconnection. The width is more preferably 0.5 mm or more, and even more preferably 1 mm or more. On the other hand, if the width exceeds 50 mm, there is a risk that the necessary plating thickness cannot be ensured. The width is more preferably 20 mm or less, and even more preferably 10 mm or less.

[0020] Although the method for forming the plating layer is not particularly limited, it is preferable to form the plating layer on the surface of the ceramic base material by electroless plating. The above problem can also be solved by providing the manufacturing method of the cooking utensil for forming the plating layer on the surface of the ceramic base material by electroless plating.

[0021] At this time, it is more preferable to roughen a part of the surface of the ceramic base material by irradiating the part with a laser, and then perform electroless plating to form wiring made of the plating layer on the surface of the part, because this makes it easy to accommodate various wiring patterns and reduces the occurrence of defective products.

[0022] In order to prevent the electroless plating catalyst described later from adhering to the region where the wiring 4 should not be formed, the ceramic base material 2 may be subjected to a protective treatment as necessary before the surface of the ceramic base material 2 is irradiated with a laser. Such a protective treatment may be performed when the ceramic base material 2 has voids (voids). Examples of the protective treatment method include a method of forming a protective film using a coating agent such as a general organic-inorganic hybrid glass coating agent or an inorganic glass coating agent, and a method of applying a water repellent agent or a coupling agent. When a protective film is formed, the protective film may be removed as necessary after forming the plating layer. Examples of the coating agent include an organic-inorganic hybrid glass coating agent such as "Protector HB-LTC2" manufactured by Okuno Chemical Industries Co., Ltd. Examples of the water repellent agent include "KBM-3063" manufactured by Shin-Etsu Chemical Co., Ltd.

[0023] The surface of the ceramic base 2 is roughened by irradiating a laser to an area where the wiring 4 is to be formed on the surface of the ceramic base 2. The roughening of the interface between the ceramic base 2 and the plating layer improves the adhesion between the ceramic base 2 and the plating layer.

[0024] Although the method of laser irradiation is not particularly limited, it is preferable to irradiate the region with a pulsed laser, since this can efficiently roughen the surface of the ceramic base material 2. Generally, the pulse width (seconds) of the pulsed laser is 1×10 -18 1×10 seconds or more -4 sec or less, the frequency is 1 to 10,000 kHz, and the average output at the processing point is 0.01 to 1,000 W. The type of laser is not particularly limited, and solid lasers such as YAG lasers, fiber lasers, and semiconductor lasers; gas lasers such as carbon dioxide lasers and excimer lasers can be used. The wavelength of the pulse laser is not particularly limited, and can be appropriately set depending on the type of ceramic substrate, and is usually 100 to 12,000 nm.

[0025] It is preferable that grooves are formed on the surface of the ceramic base material 2 and that the plating layer is filled in the grooves. This makes the wiring 4 made of the plating layer less likely to be damaged and further increases the temperature rise rate of the upper surface of the ceramic base material 2. At this time, from the viewpoint of protecting the wiring 4, it is preferable that the thickness of the plating layer and the depth of the groove are the same, or that the thickness of the plating layer is smaller than the depth of the groove. Although there is no particular limitation on the method of forming the grooves, examples include a method of forming grooves on the surface of the ceramic base material 2 by irradiating the surface of the ceramic base material 2 with a laser. It is preferable to simultaneously roughen the interface of the ceramic base material 2 and form the grooves by irradiating the surface of the ceramic base material 2 with a laser.

[0026] The depth of the groove is preferably 0.1 to 1000 μm. If the depth of the groove is less than 0.1 μm, the plating layer may easily come off from the groove. The depth of the groove is more preferably 1 μm or more, and even more preferably 5 μm or more. On the other hand, if the depth of the groove exceeds 1000 μm, the cost of forming the groove may increase. The depth of the groove is more preferably 300 μm or less, and even more preferably 100 μm or less.

[0027] The thickness of the ceramic base 2 at the portion where the wiring 4 is formed is preferably 0.3 to 30 mm. When the thickness is 0.3 mm or more, the strength of the ceramic base 2 is improved. The thickness is more preferably 0.5 mm or more, and further preferably 1 mm or more. On the other hand, when the thickness is 30 mm or less, the temperature rise rate of the ceramic base 2 is further increased and power consumption is further reduced. The thickness is more preferably 25 mm or less, and further preferably 20 mm or less.

[0028] By performing electroless plating on the region of the ceramic base material 2 irradiated with the laser, wiring 4 consisting of the plating layer is formed on the surface of the region. An electroless plating catalyst is attached to the surface of the ceramic base material 2. The electroless plating catalyst is not particularly limited, and may be any catalyst containing a metal element that has a catalytic effect on the electroless plating solution. Examples of the metal element include palladium (Pd), silver (Ag), copper (Cu), nickel (Ni), aluminum (Al), iron (Fe), cobalt (Co), zinc (Zn), gold (Au), platinum (Pt), and tin (Sn). These metal elements can be appropriately selected depending on the type of electroless plating solution. As the electroless plating catalyst, a general one can be used. For example, "A-10X" manufactured by Uemura Kogyo Co., Ltd. and "PT-4" manufactured by World Metal Co., Ltd. can be mentioned. Then, the ceramic base material 2 is treated with an aqueous solution containing the above-mentioned metal element, and then treated with an aqueous solution containing a reducing agent to activate the electroless plating catalyst.

[0029] Before plating, it is preferable to selectively remove the catalyst attached to the portion not irradiated with the laser or selectively deactivate the catalyst. As a specific method for this, the methods described in

[0044] to

[0050] of JP 2020-113469 A are adopted.

[0030] By performing electroless plating, the plating layer is formed in the area irradiated with the laser. Electroless plating may be performed multiple times. After electroless plating, electrolytic plating may be performed. When plating is performed multiple times, the types of plating layers formed may be the same or different. For example, in consideration of wear due to contact with the terminal of the power supply device 3, a copper plating layer, a gold plating layer, a silver plating layer, a tin plating layer, etc. may be further formed on the connection parts 5 at both ends of the wiring 4 (see Figures 1 and 2). A general electroless plating solution can be used. For example, electroless Ni-WP plating solutions include "Trialoy NWP" manufactured by Uemura Kogyo Co., Ltd., "Linden NPW" and "Nibotalin" manufactured by World Metal Co., Ltd.

[0031] As a method for forming wiring 4 consisting of the plating layer on the surface of the ceramic base material 2 by performing electroless plating, a method in which the surface of the ceramic base material 2 is masked so that only the portion where the plating layer is to be formed is exposed, and then electroless plating is performed to form wiring 4 consisting of the plating layer is also preferred.

[0032] From the viewpoint of safety and durability of the wiring, it is preferable that an insulating layer is formed on the surface of the wiring. The type of the insulating layer formed on the surface of the ceramic base material 2 and the wiring 4 is not particularly limited, but a glass layer (glass coat, glass sheet, etc.) and a resin layer are preferable. The thickness of the insulating layer is usually 0.1 to 100 μm.

[0033] The ceramic base material 2 is heated by passing electricity through the wiring 4 formed on the surface of the ceramic base material 2 thus obtained. The method of supplying power at this time is not particularly limited. An example of a preferred embodiment of the cooking utensil of the present invention is a cooking utensil including the ceramic base material on which wiring is formed and a housing having a power supply device that accommodates the ceramic base material and supplies power to the wiring. From the viewpoint of ease of cleaning the ceramic base material after use, it is preferable that the ceramic base material is detachable from the housing. The cooking utensil of the present invention has a high temperature rise rate and low power consumption. Moreover, since the ceramic base material can be heated uniformly, uneven baking and burning are unlikely to occur, and the cooking utensil can be made thin. Therefore, the cooking utensil is suitable for use in both home and commercial use. EXAMPLES

[0034] The present invention will now be described in more detail with reference to examples.

[0035] Example 1 The underside surface of a commercially available petalite-based heat-resistant ceramic plate (Toceram plate "Yaki-Zanmai" manufactured by Tokasa Ceramics Co., Ltd., plate size: 24.5 cm x 17.5 cm) was irradiated with laser (wavelength: 1064 nm, frequency: 50 kHz, output: 20 W) using a fiber laser marker "ML-7350DL-3D" manufactured by Amada Weld Tech Co., Ltd. to form a groove pattern (a meandering pattern consisting of approximately S-shaped repeating units) 30 μm deep and 1.5 mm wide, and the bottom surface of the groove was roughened.

[0036] The ceramic plate that had been irradiated with the laser was immersed in "A-10X" manufactured by Uemura Kogyo Co., Ltd. for 30 seconds, and then washed three times with ion-exchanged water to attach a catalyst to the groove pattern. The ceramic plate was immersed in an electroless Ni-WP plating solution of pH 9.0 kept at 90°C for 60 minutes to perform an electroless plating process, and then washed three times with ion-exchanged water. "Trialoy NWP" manufactured by Uemura Kogyo Co., Ltd. was used as the electroless Ni-WP plating solution. In this way, wiring 4 consisting of an electroless Ni plating layer with a thickness of 10 μm and a width of 1.5 mm was formed on the bottom surface of the groove of the ceramic plate.

[0037] An insulating layer having a thickness of 1 μm was formed on the surface of the electroless Ni-WP plating layer by applying "Protector S-6140" manufactured by Okuno Chemical Industries Co., Ltd. Figure 1 is a photograph showing the appearance of the underside of a ceramic substrate 2 on which wiring 4 made of a plating layer, with connection parts 5 formed on both ends, is formed.

[0038] The ceramic base material thus obtained, on whose surface the wiring made of a meandering plating layer consisting of approximately S-shaped repeating units was formed, was placed on a power supply device 3. FIG. 2 is an external photograph of a cooking utensil 1 in which a ceramic base material 2 was placed on a power supply device 3. With the connection part of the ceramic base material 2 in contact with the terminal of the power supply device 3, the ceramic base material 2 was placed on the power supply device 3, and electricity was applied to the wiring for 12 minutes at a power of 100 W (resistance value between both ends of the wiring was set to 74 Ω, AC 100 V). The temperature change of the upper surface of the ceramic base material 2 at this time was measured by thermography. The obtained thermography image is shown in FIG. 3. FIG. 4 shows a graph in which the temperature (vertical axis) of the upper surface of the ceramic base material 2 (part corresponding to the wiring) is plotted against the current application time (horizontal axis).

[0039] Comparative Example 1 A commercially available hot plate for cooking (power consumption 580 W, plate size 25.5 cm x 23 cm) equipped with a metallic front plate, a film heater placed on the underside of the front plate, and a back plate placed on the underside of the front plate was used to measure the temperature change on the plate surface using thermography when electricity was applied. Figure 3 shows the thermography image. Figure 4 shows a graph plotting the temperature at the center of the plate surface (vertical axis) against the time of electricity application (horizontal axis). Note that white smoke and an unusual odor began to come out of the hot plate 6 minutes after electricity was applied, so electricity was stopped.

[0040] As shown in Figures 3 and 4, the cooking device of the present invention, in which wiring made of a plating layer is formed on the surface of a ceramic substrate, has a higher heating rate and consumes less power than a commercially available hot plate using a film heater. Moreover, the upper surface of the ceramic substrate (the part corresponding to the wiring) heats up uniformly. Note that Figure 3 was created by converting a color image into a grayscale image, so the center of the heating part where the wiring is formed appears black (darker), but in reality the temperature was higher the closer to the center. [Explanation of symbols]

[0041] 1 Heating cooking utensils 2. Ceramic substrate 3 Power supply device 4. Wiring 5 Connection

Claims

1. A cooking device for heating, comprising a ceramic base material having wiring formed of a plating layer on the surface thereof, the ceramic base material being heated by passing an electric current through the wiring.

2. The cooking utensil according to claim 1 , wherein the plating layer contains Ni, P and W.

3. The cooking utensil according to claim 1 or 2, wherein an insulating layer is formed on a surface of the plating layer.

4. The cooking device according to claim 1 or 2, further comprising a housing that houses the ceramic base on which the wiring is formed and has a power supply device that supplies power to the wiring.

5. The method for manufacturing a cooking utensil according to claim 1 or 2, wherein the plating layer is formed on the surface of the ceramic base by electroless plating.

6. A pulsed laser is irradiated onto a portion of a surface of the ceramic base material to roughen the surface of the portion; The method for manufacturing a cooking utensil according to claim 5 , wherein the plating layer is formed on the surface of the region by performing the electroless plating.

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