Cooking utensil and preparation method thereof

Abstract

The invention relates to a cooking utensil and a preparation method thereof. The cooking utensil comprises a cooking container provided with a cooking cavity, the cooking cavity is defined by the bottom wall and the side wall of the cooking container, the bottom wall is formed by a carbon matrix, or the bottom wall and at least part of the side wall are formed by the carbon matrix, the carbon matrix comprises a carbonaceous framework and amorphous carbon materials and mineral materials, and the gaps of the carbonaceous framework are filled with the amorphous carbon materials and the mineral materials. A graphite matrix is arranged on part of the surface or inside the carbon matrix, and an organic matter carbonization layer is arranged between the carbon matrix and the graphite matrix; the cooking container also satisfies the following conditions: (1) the heat conductivity coefficient of the carbon matrix is less than the heat conductivity coefficient of the graphite matrix; and (2) the expansion coefficient of the carbon matrix is larger than that of the organic matter carbonization layer and larger than that of the graphite matrix. According to the cooking utensil, various heating modes such as electromagnetic heating can be achieved, the heating effect can be improved, and the risk that the cooking utensil cracks due to heating is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of household electrical appliances, and in particular to a cooking vessel and a preparation method thereof. Background Art

[0002] As people's living standards continue to improve, the requirements for food safety and health are also increasing. As an indispensable kitchen appliance in people's daily life, cooking utensils need to have certain safety and health. Although traditional iron, stainless steel and other cooking utensils are stable and reliable, they will release harmful substances such as iron ions and nickel ions, which have a certain impact on human health. Therefore, in recent years, some new materials have been widely studied and applied in cooking utensils to meet people's needs for safety and health.

[0003] Among them, amorphous carbon materials, as a new type of material, have attracted much attention in the field of cooking utensils. Amorphous carbon materials are a type of carbonaceous material that has the characteristics of loose structure, high porosity, and large specific surface area, so they have good adsorption and catalytic properties. In cooking utensils, amorphous carbon materials can regulate water quality, release minerals, and perform far-infrared heating, thereby improving cooking results. For example, when used in the inner pot of an electric rice cooker, it can improve the taste of rice, making it softer, more fragrant, and sweeter; when used in the inner pot of an electric stew pot, it can improve the soup-making effect of the electric stew pot, making the soup thicker, fresher, and more fragrant.

[0004] However, high-end rice cookers, conventional induction cookers and other cooking utensils use electromagnetic heating technology, which can quickly heat the inner pot with extremely high thermal efficiency. During the heating process, a high and low temperature difference is generated on the inner pot, thereby making the food roll and heat more evenly. However, amorphous carbon materials are not conductive and cannot be electromagnetically heated, nor can they achieve effective high and low temperature heating, and thus cannot achieve the heating effect of flipping and boiling food. Summary of the invention

[0005] Based on this, it is necessary to provide a cooking vessel and a preparation method thereof to address the above problems; the cooking vessel is used in cooking utensils and can realize multiple heating methods such as electromagnetic heating, which can not only improve the heating effect but also reduce the risk of cracking of the heatable components due to heat.

[0006] A cooking vessel, used for cooking utensils, the cooking vessel comprising a cooking container provided with a cooking cavity, the cooking container comprising a bottom wall and a side wall, the bottom wall and the side wall together enclose a cooking cavity, wherein a carbon matrix constitutes the bottom wall, or the carbon matrix constitutes the bottom wall and at least a part of the side wall, the carbon matrix comprises a carbon skeleton and an amorphous carbon material and a mineral material filled in the gap of the carbon skeleton, a graphite matrix is ​​arranged on a part of the surface or inside of the carbon matrix, and an organic carbonized layer is arranged between the carbon matrix and the graphite matrix;

[0007] The cooking container also simultaneously meets the following conditions:

[0008] (1) The thermal conductivity of the carbon matrix is less than that of the graphite matrix;

[0009] (2) The expansion coefficient of the carbon matrix is greater than that of the organic carbonized layer, and the expansion coefficient of the organic carbonized layer is greater than that of the graphite matrix.

[0010] The cooking utensil described in the present invention has a unique structure. On the one hand, it can achieve multiple heating methods such as electromagnetic heating; on the other hand, during the heating process, since the thermal conductivity of the graphite matrix is higher than that of the carbon matrix, and the heat conduction area of the carbon matrix is greater than that of the graphite matrix, a specific cold and hot temperature difference will be formed on the heating surface, so that effective high and low temperature heating can be achieved, accelerating the heat convection and the tumbling of the heated substance, and further improving the heating effect.

[0011] In addition, the thermal expansion coefficients of the carbon matrix, the organic carbonized layer, and the graphite matrix form a gradient, which has a transitional effect, making the overall stress controllable during the heating process, and is beneficial to reducing risks such as cracking of the cooking utensil due to heat. At the same time, the cooking utensil also has advantages such as the high hardness of amorphous carbon, not easy to shed black, and good heat storage effect, which is beneficial to improving the cooking effect.

[0012] In one embodiment, the surface of the carbon matrix is provided with a groove, and the graphite matrix is located in the groove;

[0013] Or, a cavity is provided inside the carbon matrix, and the graphite matrix is located in the cavity.

[0014] By embedding the graphite matrix into the carbon matrix, it is not only beneficial to improve the heat conduction effect, but also can reduce the exposed surface of the graphite and improve problems such as black shedding on the graphite surface.

[0015] In one embodiment, the depth of the groove or the cavity is not greater than 2 / 3 of the thickness of the carbon matrix.

[0016] By regulating the depth of the groove, it is not only beneficial to improve the electromagnetic heating effect, but also can keep the surface carbon matrix with higher strength and avoid defects such as cracks during the heating process.

[0017] In one embodiment, the carbon matrix meets at least one of the following conditions:

[0018] (1) The expansion coefficient of the carbon matrix is 4×10 -6 / °C - 6×10 -6 / °C;

[0019] (2) The porosity of the carbon matrix is greater than 6%;

[0020] (3) The thermal conductivity of the carbon matrix is 5 W / (m·K) - 20 W / (m·K).

[0021] In one embodiment, the graphite matrix satisfies at least one of the following conditions:

[0022] (1) The expansion coefficient of the graphite matrix is 2×10 -6 / °C - 3×10 -6 / °C;

[0023] (2) The porosity of the graphite matrix is greater than 6%;

[0024] (3) The thermal conductivity of the graphite matrix is 30 W / (m·K) - 100 W / (m·K).

[0025] By regulating the expansion coefficients and thermal conductivities of the carbon matrix and the graphite matrix, it is beneficial to further improve the heating effect and overall stability of the cooking utensil; by regulating the porosities of the carbon matrix and the graphite matrix, it can promote the embedding of the organic carbonized material into the carbon matrix and the graphite matrix, enhance the bonding force, and improve the interface stability.

[0026] In one embodiment, the expansion coefficient of the organic carbonized layer is 3×10 -6 / °C - 4×10 -6 / °C.

[0027] The organic carbonized layer has a specific expansion coefficient, which can make the gradient change rate of the thermal expansion coefficients between the carbon matrix, the organic carbonized layer, and the graphite matrix relatively slow, which is beneficial to further improve the overall stability of the cooking utensil and reduce the risks such as cracking.

[0028] In one embodiment, some of the organic carbonized materials in the organic carbonized layer are embedded inside the carbon matrix and the graphite matrix.

[0029] In the structure of the cooking utensil, the organic carbonized materials form an "anchor bolt" structure, which greatly increases the bonding force between the carbon matrix and the graphite matrix, thereby further reducing the risks such as cracking of the cooking utensil when heated.

[0030] In one embodiment, the graphite matrix is at least one graphite block with central symmetry or axial symmetry.

[0031] In one embodiment, the graphite matrix is a graphite block, and the central axis of the graphite matrix coincides with the central axis of the carbon matrix;

[0032] Alternatively, the graphite matrix is composed of multiple graphite blocks, which are centrosymmetrically or axially symmetrically distributed, and the central axes of the multiple graphite blocks coincide with the central axis of the carbon matrix.

[0033] By designing the shape and distribution of the graphite matrix, the heated substance can be evenly heated, which is beneficial to improving the heating effect.

[0034] A preparation method of a cooking utensil as described above includes the following steps:

[0035] Mix and press the carbon-based powder, mineral powder, and the first organic binder to form a first green body.

[0036] Use the second organic binder to combine the first green body with the graphite matrix to obtain a second green body.

[0037] Sinter the second green body at 500°C - 1000°C to obtain the cooking utensil.

[0038] In the preparation method of the present invention, by subjecting the integrally formed second green body to high-temperature sintering at 500°C - 1000°C, on the one hand, the carbon-based powder in the first green body is transformed into amorphous carbon material, which is beneficial to improving the hardness and heat storage effect of the heatable component; on the other hand, the liquid in the second organic binder evaporates and gasifies, and the residual organic matter carbonizes and partially embeds into the interiors of the carbon matrix and the graphite matrix to form an organic matter carbonized layer, constituting an "anchor bolt" structure, greatly increasing the bonding force between the carbon matrix and the graphite matrix, improving the interface stability, and further reducing the risks such as cracking of the cooking utensil during heating.

[0039] In one embodiment, the carbon-based powder satisfies at least one of the following conditions:

[0040] (1) The mass fraction of the carbon-based powder in the first green body is 50% - 80%;

[0041] (2) The particle size of the carbon-based powder is 100 mesh - 1000 mesh;

[0042] (3) The carbon-based powder is selected from at least one of bamboo charcoal powder, charcoal powder, binchotan powder, graphite powder, or carbon fiber powder.

[0043] In one embodiment, the mineral powder satisfies at least one of the following conditions:

[0044] (1) The mass fraction of the mineral powder in the first green body is 10% - 40%;

[0045] (2) The particle size of the mineral powder is 100 mesh - 1000 mesh;

[0046] (3) The mineral powder is selected from at least one of medical stone powder and tourmaline powder.

[0047] By regulating the content, particle size and type of the carbon-based powder and the mineral powder in the first green body, it is not only beneficial to ensure that the cooking utensil has good heat conduction performance, but also can ensure that the water quality in contact with the cooking utensil is maintained within a suitable pH value range, so as to meet people's requirements for health.

[0048] In one embodiment, the first organic binder and the second organic binder are respectively and independently selected from at least one of epoxy resin solution and phenolic resin solution.

[0049] The first organic binder can effectively bond the carbon-based powder and the mineral powder together, and form a carbonaceous skeleton through sintering and carbonization, so that the amorphous carbon material and the mineral material are filled in the gaps of the carbonaceous skeleton, improving the strength of the carbon matrix. The second organic binder can bond the first green body to the graphite matrix and fill the pores between the first green body and the graphite matrix, improving the bonding effect.

[0050] In one embodiment, the step of bonding the first green body to the graphite matrix using the second organic binder satisfies at least one of the following conditions:

[0051] (1) The solid content of the second organic binder is 30%-60%;

[0052] (2) The graphite matrix is selected from at least one of isostatic graphite, molded graphite or extruded graphite;

[0053] (3) The thickness of the graphite matrix is 1 / 3 - 2 / 3 of the thickness of the first green body;

[0054] (4) After bonding the first green body to the graphite matrix using the second organic binder, a pressure treatment is further included.

[0055] By regulating the preparation conditions in the step of bonding the first green body to the graphite matrix using the second organic binder, it is beneficial to improve the bonding force and interface stability between the carbon matrix and the graphite matrix obtained after sintering.

[0056] In one embodiment, the sintering is carried out in a protective atmosphere, which is beneficial to improving the carbonization effect and further improving the heat conduction of the obtained cooking utensil.

[0057] Therefore, using the cooking utensil of the present invention in a cooking appliance can realize various heating methods such as electromagnetic heating, not only improving the heating effect, but also reducing the risks such as the cooking utensil cracking due to heat, meeting the various requirements of the cooking appliance in terms of safety and health. Description of the Drawings

[0058] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0059] Figure 1 It is a schematic cross-sectional structure diagram of a cooking utensil in an embodiment of the present invention;

[0060] Figure 2 It is a schematic cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0061] Figure 3 It is a schematic cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0062] Figure 4 It is a schematic side cross-sectional structure diagram of a cooking utensil in an embodiment of the present invention;

[0063] Figure 5 It is Figure 4 a schematic bottom cross-sectional structure diagram of the shown cooking utensil;

[0064] Figure 6 It is a schematic side cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0065] Figure 7 It is a schematic side cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0066] Figure 8 It is Figure 7 a schematic bottom cross-sectional structure diagram of the shown cooking utensil;

[0067] Figure 9 It is a schematic bottom cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0068] Figure 10 It is a schematic bottom cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0069] Figure 11 It is a schematic side cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention;

[0070] Figure 12 It is Figure 11 a schematic bottom cross-sectional structure diagram of the shown cooking utensil;

[0071] Figure 13 It is a schematic side cross-sectional structure diagram of a cooking utensil in another embodiment of the present invention.

[0072] Among them, 10 is a cooking utensil; 101 is a carbon matrix; 102 is an organic matter carbonized layer; 103 is a graphite matrix; 104 is a glass side wall. Specific embodiments

[0073] For the convenience of understanding the present invention, the present invention will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. On the contrary, these embodiments or examples are provided to make the understanding of the disclosure content of the present invention more thorough and comprehensive.

[0074] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments or examples and are not intended to limit the present invention.

[0075] Combined with Figure 1 As shown, a cooking utensil provided by the present invention is used for a cooking appliance. The cooking utensil includes a cooking container provided with a cooking cavity. The cooking container includes a bottom wall and a side wall. The bottom wall and the side wall enclose the cooking cavity. Among them, the carbon matrix 101 constitutes the bottom wall, or the carbon matrix 101 constitutes the bottom wall and at least part of the side wall. The carbon matrix 101 includes a carbonaceous skeleton and amorphous carbon materials and mineral materials filled in the gaps of the carbonaceous skeleton. The graphite matrix 103 is disposed on part of the surface or inside of the carbon matrix 101, and the organic matter carbonized layer 102 is disposed between the carbon matrix 101 and the graphite matrix 103.

[0076] It should be noted that when the graphite matrix 103 is disposed inside the carbon matrix 101, it can be understood that the volume of the carbon matrix 101 must be greater than the volume of the graphite matrix 103. Since the graphite matrix 103 is disposed on part of the surface or inside of the carbon matrix 101, in the actual application scenario of the cooking utensil, under the preset electromagnetic heating area, the heat conduction area of the carbon matrix 101 mapped to the electromagnetic heating device must be greater than the heat conduction area of the graphite matrix 103 mapped to the electromagnetic heating device. Specifically, combined with Figure 1 As shown, the heat conduction area of the graphite matrix 103 is S1, and the heat conduction area of the carbon matrix 101 is S2.

[0077] Furthermore, due to the unique structure of the cooking utensil according to the present invention, on the one hand, various heating methods such as electromagnetic heating can be achieved; on the other hand, during the heating process, since the thermal conductivity coefficient of the graphite matrix 103 is higher than that of the carbon matrix 101, and the heat conduction area of the carbon matrix 101 is larger than that of the graphite matrix 103, a specific cold and hot temperature difference will be formed on the heating surface, thereby enabling effective high and low temperature heating, accelerating heat convection and the tumbling of the heated substance, and further improving the heating effect.

[0078] In addition, since the expansion coefficient of the carbon matrix 101 is greater than that of the organic matter carbonized layer 102, and the expansion coefficient of the organic matter carbonized layer 102 is greater than that of the graphite matrix 103, a gradient of the thermal expansion coefficients among the carbon matrix 101, the organic matter carbonized layer 102, and the graphite matrix 103 is formed, which has a transitional effect, making the overall stress controllable during the heating process and facilitating the reduction of risks such as cracking of the cooking utensil due to heat. At the same time, the cooking utensil also has advantages such as the high hardness of amorphous carbon, not being prone to blackening, and good heat storage effect, which are beneficial to improving the cooking effect.

[0079] In one embodiment, as shown in Figure 1 , grooves are provided on the surface of the carbon matrix 101, and the graphite matrix 103 is located in the grooves; or, as shown in Figure 2 , a cavity is provided inside the carbon matrix 101, and the graphite matrix 103 is located in the cavity. By embedding the graphite matrix 103 into the carbon matrix 101, it is not only beneficial to improve the heat conduction effect, but also can reduce the exposed surface of the graphite and improve problems such as blackening on the graphite surface.

[0080] It should be noted that the organic matter carbonized layer 102 is in contact with at least one surface of the graphite matrix 103. Taking the structure shown in Figure 2 as an example, the organic matter carbonized layer 102 can be in contact with three surfaces of the graphite matrix 103, or only in contact with one surface of the graphite matrix 103, or in contact with four surfaces of the graphite matrix 103. The present invention does not limit this.

[0081] Preferably, the depth of the groove or the cavity is not greater than 2 / 3 of the thickness of the carbon matrix 101, which is not only beneficial to improving the electromagnetic heating effect, but also can keep the surface carbon matrix 101 with higher strength and avoid defects such as cracks during the heating process.

[0082] It should be noted that the depth of the groove or the cavity refers to the farthest distance from the groove or the cavity to the outer surface of the carbon matrix.

[0083] In one embodiment, the carbon matrix 101 satisfies at least one of the following conditions:

[0084] (1) The expansion coefficient of the carbon matrix 101 is 4×10 -6 / °C - 6×10 -6 / °C;

[0085] (2) The porosity of the carbon matrix 101 is greater than 6%;

[0086] (3) The thermal conductivity of the carbon matrix 101 is 5 W / (m·k) - 20 W / (m·k).

[0087] In one embodiment, the graphite matrix 103 satisfies at least one of the following conditions:

[0088] (1) The expansion coefficient of the graphite matrix 103 is 2×10 -6 / °C - 3×10 -6 / °C;

[0089] (2) The porosity of the graphite matrix 103 is greater than 6%;

[0090] (3) The thermal conductivity of the graphite matrix 103 is 30 W / (m·k) - 100 W / (m·k).

[0091] By regulating the porosity of the carbon matrix 101 and the graphite matrix 103, it is beneficial to promote the embedding of the organic matter carbonized material into the carbon matrix 101 and the graphite matrix 103, enhance the bonding force, and improve the interface stability; by regulating the expansion coefficient and thermal conductivity of the carbon matrix 101 and the graphite matrix 103, it is beneficial to further improve the heating effect and overall stability of the cooking utensil.

[0092] In one embodiment, the expansion coefficient of the organic matter carbonized layer 102 is 3×10 -6 / °C - 4×10 -6 / °C, making the gradient change rate of the thermal expansion coefficients between the carbon matrix 101, the organic matter carbonized layer 102, and the graphite matrix 103 relatively slow, which is beneficial to further improve the overall stability of the cooking utensil and reduce the risks such as cracking.

[0093] In one embodiment, as shown in Figure 3 and some of the organic matter carbonized materials in the organic matter carbonized layer 102 are embedded into the interiors of the carbon matrix 101 and the graphite matrix 103, enabling the organic matter carbonized materials to form an "anchor bolt" structure, greatly increasing the bonding force between the carbon matrix 101 and the graphite matrix 103, and thus further reducing the risks such as the cooking utensil cracking when heated.

[0094] In one embodiment, the embedding depth of the partial organic matter carbonized materials is preferably 10 μm - 200 μm, which is more beneficial to enhancing the bonding force between the carbon matrix 101 and the graphite matrix 103.

[0095] In one embodiment, the graphite matrix 103 is at least one graphite block with central symmetry or axial symmetry.

[0096] Specifically, the graphite matrix 103 is one graphite block, and the central axis of the graphite matrix 103 coincides with the central axis of the carbon matrix 101; or, the graphite matrix 103 is multiple graphite blocks, and the multiple graphite blocks are distributed with central symmetry or axial symmetry and the central axis of the multiple graphite blocks coincides with the central axis of the carbon matrix 101.

[0097] Among them, the shape of the graphite block includes but is not limited to symmetric shapes such as circular, circular ring-shaped, sector ring-shaped, rectangular, etc., which can make the heated substance receive heat evenly and is beneficial to improving the heating effect.

[0098] When the bottom wall and side wall of the cooking utensil are all directly constituted by the carbon matrix 101, the cooking utensil has an integrated structure and can be applied to the inner liner of an electric rice cooker, the inner liner of an electric slow cooker, a soup pot, etc.

[0099] Specifically, in one embodiment, referring to Figure 4 the schematic side sectional structure diagram of the cooking utensil 10 shown, the graphite matrix 103 is arranged at the bottom of the cooking utensil 10 in a disc shape, and the specific bottom sectional structure is as Figure 5 shown. In an electromagnetic heating environment or other heating environments, the graphite matrix 103 absorbs heat or generates heat, and then longitudinally transfers it to the corresponding part of the vertical surface carbon matrix 101, forming a temperature difference between hot and cold on the inner surface. During the process of heating food or water, the heat spreads from high to low, and then generates bubble transfer as shown in Figure 4 i.e., a 180° to 360° water flow tumbling is generated at the edge of the area corresponding to the graphite matrix 103, accelerating the heat convection and the tumbling of the cooked food, improving the cooking effect, and can be applied to products such as electric rice cookers, electric slow cookers, soup pots, etc.

[0100] In another embodiment, referring to Figure 6 the schematic side sectional structure diagram of the cooking utensil 10 shown, the graphite matrix 103 can also be arranged at both the bottom and the side of the cooking utensil 10, which is beneficial to improving the overall heat conduction effect and heat uniformity, and can be applied to products such as electric rice cookers, electric slow cookers, soup pots, etc.

[0101] Therefore, the graphite matrix 103 is not limited to being arranged at the bottom of the cooking utensil 10, and can also be arranged on the side wall of the cooking utensil 10, and the number can be one or more, making the cooking utensil 10 receive heat more evenly and have a higher heating efficiency. The present invention does not limit this.

[0102] In another embodiment, referring to Figure 7 and Figure 8Schematic cross-sectional structure diagrams of the cooking utensil 10 shown at different angles. The graphite matrix 103 is composed of multiple circular graphite blocks distributed symmetrically in an array and is located at the bottom of the cooking utensil 10. In an electromagnetic heating environment or other heating environments, the graphite matrix 103 will absorb heat or generate more heat, and the heat will be quickly propagated longitudinally to the surface of the carbon matrix 101, thereby forming a part where multiple hot zones and cold zones are combined on the surface of the carbon matrix 101. During the process of cooking food, multiple boiling points are formed at this part, creating a temperature difference with the cold zones, causing the water, soup, food, etc. being cooked to flow and boil, improving the cooking effect. It can be applied to products such as rice cookers, electric slow cookers, and soup pots.

[0103] In another embodiment, referring to Figure 9 as shown, the graphite matrix 103 is distributed in the form of two nested circular graphite blocks at the bottom of the cooking utensil 10.

[0104] In another embodiment, referring to Figure 10 as shown, the graphite matrix 103 is composed of multiple trapezoidal or fan-shaped ring graphite blocks distributed symmetrically at equal intervals and is located at the bottom of the cooking utensil 10.

[0105] In another embodiment, referring to Figure 11 and Figure 12 Schematic cross-sectional structure diagrams of the cooking utensil 10 shown at different angles. The graphite matrix 103 is distributed in a curved circular ring shape at the hemispherical bottom of the cooking utensil 10.

[0106] It should be noted that the above cooking utensil 10 is not limited to electromagnetic heating. Products such as soup pots can also be applicable to other heating methods such as open flames, and the present invention does not limit this.

[0107] When the carbon matrix 101 is only used as the bottom wall of the cooking utensil 10, other materials can be used as the side wall of the cooking utensil 10, and they are assembled with the carbon matrix 101 to form the cooking utensil 10, such as products like electric kettles and health kettles.

[0108] Specifically, in one embodiment, referring to Figure 13 the schematic side cross-sectional structure diagram of the cooking utensil 10 shown, the carbon matrix 101 is used as the bottom wall and is assembled with the glass side wall to form the cooking utensil 10. Among them, the graphite matrix 103 in the bottom wall is 1 circular ring-shaped graphite block. The bottom cross-section of the cooking utensil 10 is Figure 12 similar, and the present invention will not repeat the drawing for illustration. This cooking utensil 10 can be subjected to electromagnetic heating or resistive heating, and by forming heat convection, the cooking effect is improved. It can be applied to products such as electric kettles and health kettles.

[0109] It should be noted that after a coating is provided on the exposed surface of the graphite matrix 103, it can be used as the outer surface of the cooking utensil or the inner surface of the cooking utensil, and the present invention does not limit this.

[0110] When the cooking utensil 10 described in the present invention is used in a cooking appliance, various heating methods such as electromagnetic heating can be realized, which can not only improve the heating effect, but also reduce the risks such as the cooking utensil cracking due to heat, meeting the requirements of the cooking appliance in terms of safety, health and other aspects.

[0111] The present invention provides a preparation method of the cooking utensil 10 as described above, comprising the following steps:

[0112] S1, mixing carbon-based powder, mineral powder and a first organic binder and pressing them into a shape to obtain a first green body;

[0113] S2, using a second organic binder to combine the first green body with the graphite matrix 103 to obtain a second green body;

[0114] S3, sintering the second green body at 500°C - 1000°C to obtain the cooking utensil 10.

[0115] In step S1, various shapes and sizes of the first green body can be obtained by pressing and forming. Preferably, a groove for placing the graphite matrix 103 is reserved on the first green body to facilitate one-time forming.

[0116] The carbon-based powder not only has good thermal conductivity, but also has good adsorption performance and can purify water quality. In addition, the carbon-based powder also has better stability and hardness, making the manufactured cooking utensil 10 not prone to rust or deformation.

[0117] In one embodiment, the carbon-based powder satisfies at least one of the following conditions:

[0118] (1) The mass fraction of the carbon-based powder in the first green body is 50% - 80%;

[0119] (2) The particle size of the carbon-based powder is 100 mesh - 1000 mesh;

[0120] (3) The carbon-based powder is selected from at least one of bamboo charcoal powder, charcoal powder, binchotan powder, graphite powder or carbon fiber powder.

[0121] Among them, the pH values of bamboo charcoal powder, charcoal powder, binchotan powder, graphite powder and carbon fiber powder are between 8.5 - 9.5, having certain alkalinity. During the contact with water, the pH value of water can be adjusted to obtain weakly alkaline water, meeting the requirements of people for health.

[0122] In one embodiment, the mineral powder satisfies at least one of the following conditions:

[0123] (1) The mass fraction of the mineral powder in the first green body is 10% - 40%;

[0124] (2) The particle size of the mineral powder is 100 mesh - 1000 mesh;

[0125] (3) The mineral powder is selected from at least one of medical stone powder and tourmaline powder.

[0126] Among them, medical stone powder and tourmaline powder can release alkaline metal oxides such as sodium oxide, potassium oxide, and aluminum oxide, so as to be able to adjust the pH value of water to obtain weakly alkaline water, and at the same time can provide minerals beneficial to the human body, which is beneficial to enhancing the competitiveness of the product.

[0127] By controlling that the content of the carbon-based powder in the first green body is relatively large and the content of the mineral powder is relatively small, it is not only beneficial to ensure that the cooking utensil 10 has good thermal conductivity, but also can ensure that the water quality is maintained within a suitable pH value range.

[0128] In one embodiment, the first organic binder is selected from at least one of epoxy resin glue and phenolic resin glue. Since the surfaces of the carbon-based powder and the mineral powder have micropores, in the step of mixing and pressing into shape, by controlling the viscosity of the first organic binder, the binder can penetrate into some of the micropores, so as to effectively bond the carbon-based powder and the mineral powder together. Then, through sintering, the first organic binder carbonizes at a certain temperature to form a carbonaceous skeleton, and the amorphous carbon material and the mineral material are filled in the gaps of the carbonaceous skeleton, improving the strength of the carbon matrix 101.

[0129] It should be noted that the first organic binder can use existing conventional products or can be prepared by itself, and the present invention does not limit this. Taking phenolic resin as an example, the particle size of phenolic powder particles is preferably 0.1 μm - 5 μm, and diluents such as acetone and methanol can be used to prepare phenolic resin glue from phenolic powder particles. The solid content of the phenolic resin glue is preferably 30% - 60%.

[0130] In step S2, the graphite matrix 103 can be directly combined with the surface of the first green body by using the second organic binder. Preferably, the second organic binder is coated in the reserved groove of the first green body, and the graphite matrix 103 is placed in the groove to combine the first green body with the graphite matrix 103. It is also possible to cover the first green body on the surface of the graphite matrix 103 after the graphite matrix 103 is placed in the groove and press and form it again, so that the graphite matrix 103 is coated inside the first green body. The present invention does not limit this.

[0131] In one embodiment, the step of combining the first green body with the graphite matrix 103 by using the second organic binder satisfies at least one of the following conditions:

[0132] (1) The solid content of the second organic binder is 30% - 60%;

[0133] (2) The graphite matrix is selected from at least one of isostatic graphite, molded graphite, or extruded graphite;

[0134] (3) The thickness of the graphite matrix is 1 / 3 - 2 / 3 of the thickness of the first green body;

[0135] (4) After combining the first green body and the graphite matrix with a second organic binder, a pressure treatment is further included.

[0136] Due to the presence of certain pores on the surfaces of the first green body and the graphite matrix 103, the pressure treatment can promote the penetration of the second organic binder into the first green body and the graphite matrix 103, which is beneficial to the formation of carbonization of the organic matter with an "anchor bolt" structure during the subsequent sintering process, thereby improving the bonding strength and interface stability.

[0137] In one embodiment, the second organic binder is selected from at least one of epoxy resin solution and phenolic resin solution.

[0138] In step S3, through high-temperature sintering at 500°C - 1000°C, on the one hand, the carbon-based powder in the first green body is converted into amorphous carbon material, which is beneficial to improving the hardness and heat storage effect of the cooking utensil 10; on the other hand, the liquid in the second organic binder evaporates and gasifies, and the residual organic matter carbonizes and partially embeds into the interiors of the carbon matrix 101 and the graphite matrix 103 to form an organic matter carbonized layer, constituting an "anchor bolt" structure, greatly increasing the bonding strength between the carbon matrix 101 and the graphite matrix 103, improving the interface stability, and further reducing the risks such as cracking of the cooking utensil 10 when heated.

[0139] In one embodiment, the sintering is carried out in a protective atmosphere, and the protective atmosphere is selected from inert gases. Optionally, the inert gas is selected from nitrogen and / or argon, which is beneficial to improving the carbonization effect and further improving the thermal conductivity of the prepared cooking utensil 10.

[0140] In one embodiment, after the sintering is completed, a polishing treatment is further included for the cooking utensil 10. Specifically, the polishing treatment is to polish the surface of the cooking utensil 10 with polishing materials such as a scouring pad, sandpaper, or silicon carbide.

[0141] In one embodiment, by preparing a silicon carbide coating, a pyrolytic carbon coating, or an inorganic silica coating on the exposed surface of the graphite matrix 103, graphite blackening can be prevented.

[0142] Hereinafter, the cooking utensil and its preparation method will be further described through the following specific examples.

[0143] Raw materials: phenolic resin (addition amount is 3%, solid content is 50%); epoxy resin (addition amount is 5%, solid content is 45%); bamboo charcoal powder (800 mesh); charcoal powder (900 mesh); binchotan powder (1000 mesh); graphite powder (600 mesh); medical stone powder (800 mesh); tourmaline powder (800 mesh); isostatic graphite (coefficient of thermal expansion is 2×10 -6 / °C, thermal conductivity is 90 W / (m·k), porosity is 8%); molded graphite (coefficient of thermal expansion is 2.5×10 -6 / °C, thermal conductivity is 50 W / (m·k), porosity is 15%); extruded graphite (coefficient of thermal expansion is 3×10 -6 / °C, thermal conductivity is 30 W / (m·k), porosity is 25%).

[0144] Examples 1-4 are all prepared according to the cooking utensil structure shown in Figure 4 and Figure 5 .

[0145] Example 1

[0146] 200 g of bamboo charcoal powder, 200 g of charcoal powder, 200 g of binchotan powder, 150 g of medical stone powder, 150 g of tourmaline powder and 100 g of epoxy resin are evenly mixed to form a slurry, and the slurry is pressed into shape with a press and a mold to obtain a first green body with grooves. Among them, the thickness of the first green body is 6 mm, and the groove depth is 2 mm.

[0147] Epoxy resin is evenly coated in the grooves, and isostatic graphite is put in and pressurized to obtain a second green body.

[0148] In a nitrogen environment, the second green body is sintered at 1000 °C to obtain a cooking utensil.

[0149] After testing, the coefficient of thermal expansion of the carbon matrix in this cooking utensil is 4×10 -6 / °C, thermal conductivity is 20 W / (m·k) (tested according to GB / T7320-2018 coefficient of thermal expansion), porosity is 2%; the coefficient of thermal expansion of the organic carbonized layer is 3×10 -6 / °C, and the embedding depth of the organic carbonized material is 200 μm.

[0150] Example 2

[0151] 300 g of bamboo charcoal powder, 150 g of charcoal powder, 150 g of binchotan powder, 200 g of medical stone powder, 150 g of tourmaline powder and 50 g of phenolic resin are evenly mixed to form a slurry, and the slurry is pressed into shape with a press and a mold to obtain a first green body with grooves. Among them, the thickness of the first green body is 6 mm, and the groove depth is 3 mm.

[0152] Evenly apply the epoxy resin in the groove, place the static pressure graphite and apply pressure to obtain the second green body.

[0153] In a nitrogen environment, sinter the second green body at 900 °C to obtain the cooking utensil.

[0154] After testing, the expansion coefficient of the carbon matrix in the cooking utensil is 5×10 -6 / °C, the thermal conductivity is 15 W / (m·k), and the porosity is 3.5%; the expansion coefficient of the organic carbonized layer is 3.3×10 -6 / °C, and the embedding depth of the organic carbonized material is 100 μm.

[0155] Example 3

[0156] Evenly mix 300 g of charcoal powder, 300 g of binchotan powder, 300 g of tourmaline powder, and 100 g of epoxy resin to form a slurry. Use a press and a mold to press the slurry into shape to obtain the first green body with a groove. Among them, the thickness of the first green body is 6 mm, and the groove depth is 3.5 mm.

[0157] Evenly apply the epoxy resin in the groove, place the static pressure graphite and apply pressure to obtain the second green body.

[0158] In a nitrogen environment, sinter the second green body at 800 °C to obtain the cooking utensil.

[0159] After testing, the expansion coefficient of the carbon matrix in the cooking utensil is 5.5×10 -6 / °C, the thermal conductivity is 10 W / (m·k), and the porosity is 4.6%; the expansion coefficient of the organic carbonized layer is 3.7×10 -6 / °C, and the embedding depth of the organic carbonized material is 130 μm.

[0160] Example 4

[0161] Evenly mix 600 g of binchotan powder, 100 g of medical stone powder, 200 g of tourmaline powder, and 100 g of epoxy resin to form a slurry. Use a press and a mold to press the slurry into shape to obtain the first green body with a groove. Among them, the thickness of the first green body is 6 mm, and the groove depth is 4 mm.

[0162] Evenly apply the epoxy resin in the groove, place the static pressure graphite and apply pressure to obtain the second green body.

[0163] In a nitrogen environment, sinter the second green body at 500 °C to obtain the cooking utensil.

[0164] After testing, the expansion coefficient of the carbon matrix in the cooking utensil is 6×10 -6 / °C, the thermal conductivity is 5 W / (m·k) (tested according to the coefficient of thermal expansion in GB / T7320-2018), and the porosity is 6%; the coefficient of expansion of the organic carbonized layer is 4×10 -6 / °C, and the embedding depth of the organic carbonized material is 200 μm.

[0165] Comparative Example 1

[0166] The difference between Comparative Example 1 and Example 1 is that the sintering temperature is 1400 °C.

[0167] The coefficient of expansion of the carbon matrix in the cooking utensil obtained in this comparative example is 1.8×10 -6 / °C, and the coefficient of expansion of the organic carbonized layer is 3.1×10 -6 / °C.

[0168] Comparative Example 2

[0169] The difference between Comparative Example 2 and Example 1 is that epoxy resin with a solid content of 80% is evenly coated in the groove.

[0170] The coefficient of expansion of the organic carbonized layer in the cooking utensil obtained in this comparative example is 2×10 -6 / °C.

[0171] Comparative Example 3

[0172] The difference between Comparative Example 3 and Example 1 is that graphite is directly used as the blank, and the cooking utensil is obtained after sintering.

[0173] The cooking utensils prepared in Examples 1-4 and Comparative Examples 1-3 were directly used as cookware for performance testing, and the results are shown in Table 1.

[0174] Test method: Put the cooking utensil into an incubator at 420 °C, with a temperature difference of ±5 °C. After keeping warm for 30 minutes, take it out. The mouth of the cooking utensil forms an angle of about 45 degrees with the water surface, and it is put into the water at the fastest speed and soaked for 10 minutes. Take out the cooking utensil and dry it with a cloth. The above steps are one cycle, and repeat the cycle 3 times to test the thermal shock resistance of the cooking utensil.

[0175] Table 1

[0176]

[0177] As can be seen from Table 1, under electromagnetic heating conditions, the cooking utensils prepared in Examples 1-4 can achieve heat conduction and will not crack under extremely cold and hot conditions of 420 °C, with high safety in use. Compared with Examples 1-4, microcracks and cracking occurred in Comparative Examples 1-2, and blackening occurred in Comparative Example 3, so it cannot be used as a cooking utensil to directly contact food.

[0178] The technical features of the above-described embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0179] The above-described embodiments merely represent several implementation manners of the present invention. The description is relatively specific and detailed, but it should not be construed as a limitation on the scope of the invention patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can still be made, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the present invention patent shall be subject to the appended claims.

Claims

1. A cooking utensil for a cooking appliance, the cooking utensil comprising a cooking container provided with a cooking cavity, characterized in that, The cooking container includes a bottom wall and a side wall, and the bottom wall and the side wall enclose a cooking cavity. Among them, a carbon matrix forms the bottom wall, or the carbon matrix forms the bottom wall and at least part of the side wall. The carbon matrix includes a carbonaceous skeleton and amorphous carbon materials and mineral materials filled in the gaps of the carbonaceous skeleton. A graphite matrix is provided on part of the surface or inside of the carbon matrix, and an organic carbonized layer is provided between the carbon matrix and the graphite matrix; The cooking container also simultaneously meets the following conditions: (1) The thermal conductivity of the carbon matrix is less than that of the graphite matrix; (2) The expansion coefficient of the carbon matrix is greater than that of the organic carbonized layer, and the expansion coefficient of the organic carbonized layer is greater than that of the graphite matrix.

2. The cooking utensil according to claim 1, wherein The surface of the carbon matrix is provided with a groove, and the graphite matrix is located in the groove; Or, a cavity is provided inside the carbon matrix, and the graphite matrix is located in the cavity.

3. The cooking utensil according to claim 2, characterized in that, The depth of the groove or the cavity is not greater than 2 / 3 of the thickness of the carbon matrix.

4. The cooking utensil according to claim 1, wherein, The carbon matrix meets at least one of the following conditions: (1) The expansion coefficient of the carbon matrix is 4×10 -6 / °C - 6×10 -6 / °C; (2) The porosity of the carbon matrix is greater than 6%; (3) The thermal conductivity of the carbon matrix is 5W / (m·k)-20W / (m·k).

5. The cooking utensil according to claim 1, characterized in that, The graphite matrix meets at least one of the following conditions: (1) The coefficient of thermal expansion of the graphite matrix is 2×10 -6 / °C - 3×10 -6 / °C; (2) The porosity of the graphite matrix is greater than 6%; (3) The thermal conductivity of the graphite matrix is 30W / (m·k)-100W / (m·k).

6. The cooking utensil according to claim 1, characterized in that, The coefficient of thermal expansion of the organic carbonized layer is 3×10 -6 / °C - 4×10 -6 / °C.

7. The cooking utensil according to claim 1, characterized in that, Part of the organic carbonized materials in the organic carbonized layer are embedded inside the carbon matrix and the graphite matrix.

8. The cooking utensil according to claim 1, characterized in that, The graphite matrix is at least one graphite block that is centrosymmetric or axially symmetric.

9. The cooking utensil according to claim 1, wherein The graphite matrix is a graphite block, and the central axis of the graphite matrix coincides with that of the carbon matrix; Or, the graphite matrix is multiple graphite blocks, the multiple graphite blocks are centrosymmetric or axially symmetrically distributed, and the multiple graphite blocks coincide with the central axis of the carbon matrix.

10. A method for preparing a cooking utensil according to any one of claims 1-9, characterized in that, It includes the following steps: Mix and press carbon-based powder, mineral powder and a first organic binder to form a first green body; Bind the first green body with the graphite matrix using a second organic binder to obtain a second green body; Sinter the second green body at 500°C - 1000°C to obtain the cooking utensil.

11. The preparation method of the cooking utensil according to claim 10, characterized in that, The carbon-based powder meets at least one of the following conditions: (1) The mass fraction of the carbon-based powder in the first green body is 50% - 80%; (2) The particle size of the carbon-based powder is 100 mesh - 1000 mesh; (3) The carbon-based powder is selected from at least one of bamboo charcoal powder, charcoal powder, binchotan powder, graphite powder or carbon fiber powder.

12. The preparation method of the cooking utensil according to claim 10, characterized in that, The mineral powder meets at least one of the following conditions: (1) The mass fraction of the mineral powder in the first green body is 10% - 40%; (2) The particle size of the mineral powder is 100 mesh - 1000 mesh; (3) The mineral powder is selected from at least one of medical stone powder or tourmaline powder.

13. The preparation method of the cooking utensil according to claim 10, characterized in that, The first organic binder and the second organic binder are each independently selected from at least one of epoxy resin glue solution and phenolic resin glue solution.

14. The preparation method of the cooking utensil according to claim 10, characterized in that, The step of bonding the first green body to the graphite matrix using a second organic binder satisfies at least one of the following conditions: (1) The solid content of the second organic binder is 30%-60%; (2) The graphite matrix is selected from at least one of isostatic graphite, molded graphite, or extruded graphite; (3) The thickness of the graphite matrix is 1 / 3-2 / 3 of the thickness of the first green body; (4) After bonding the first green body to the graphite matrix using a second organic binder, it further includes a pressure treatment.

15. The preparation method of the cooking utensil according to claim 10, characterized in that, The sintering is carried out in a protective atmosphere.

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