Heating film and its manufacturing method, heating tube and heating electrical equipment

Abstract

This disclosure provides a heating film, a method for manufacturing the same, a heating element, and an electrical heating device. The heating film material comprises natural graphite and / or graphene, and the heating film has a thickness of 0.04 mm to 2 mm and a density of 0.6 g / cm³. 3 ~1.8g / cm 3 It satisfies at least one of the following conditions.

Description

Technical Field

[0001] The present disclosure relates to the technical field of electrical equipment, specifically, to a heating film and a manufacturing method thereof, a heating tube, and a heating electrical equipment.

Background Art

[0002] Conventional electric ovens mainly heat the air in the chamber with heating tubes to heat food and directly heat the surface of the food by heat radiation.Currently, the heating components used in heating electrical equipment such as electric ovens, microwave ovens, and steam ovens on the market mainly include metal heating tubes (the maximum heating temperature range is 550 - 750°C), quartz heating tubes (the temperature range of the heating wire is 660 - 800°C), halogen heating tubes (the maximum heating temperature is less than 1000°C), and carbon fiber heating tubes (the maximum heating temperature is less than 1000°C), etc. However, the above heating tubes have problems such as a low heating rate within the heating temperature range, insufficiently fast heat generation, and insufficient temperature, resulting in a long cooking time and difficulty in achieving a crispy outside and a soft inside for food during heating, causing discomfort to users. In addition, the adjustable range of the power of conventional heating tubes is small, further limiting its application range.

Summary of the Invention

Problems to be Solved by the Invention

[0003] The main purpose of the present disclosure is to solve at least to some extent one of the technical problems in the related art. For this reason, one objective of the present disclosure is to propose a heating film having advantages such as a high heating temperature, a fast heat generation rate, and a fast heating rate.

Means for Solving the Problems

[0004] In one aspect of the present disclosure, the present disclosure provides a heating film. According to an embodiment of the present disclosure, the material of the heating film comprises natural graphite and / or graphene, the heating film has a thickness of 0.04 mm to 2 mm, and the density of the heating film is 0.6 g / cm³. 3 ~1.8g / cm 3 It satisfies at least one of the following conditions. As a result, heating films made of graphite material produced from natural graphite or graphene have a high heating temperature, a fast heating rate, and are useful in achieving higher heating temperatures and higher heating efficiency. Furthermore, the heating film of this disclosure uses natural graphite, and natural graphite ore is abundant among Earth's minerals. At the same time, carbon-based film materials do not require high-temperature graphitization in the manufacturing process, nor do they need to be manufactured in other processes, allowing for continuous production and cost reduction. In short, carbon-based film materials have advantages such as a wide range of material sources, a simple manufacturing process, good product stability, and adjustable and easily adjustable performance parameters, which offers enormous benefits in terms of reducing product costs, increasing product reliability, and increasing the variety of products. If artificial graphite is used, it is necessary to set up a process flow for producing artificial graphite, which significantly increases the cost and time of manufacturing heating films and reduces production efficiency. However, using graphene as a raw material is advantageous in obtaining heating films with a high carbon content, and moreover, the processing process is simple and mature, and the manufacturing cost is not high. Furthermore, when the above conditions are met, the heating film can meet a wide range of power requirements, not only providing a high-power heating film but also a highly efficient heating film. At the same time, the heating film is easy to manufacture under the above conditions, meaning it has a high production yield and a lifespan that meets usage requirements.

[0005] According to the embodiments of this disclosure, the carbon content of the heating film is 99% or more.

[0006] According to the embodiments of this disclosure, the power of the heating film is 15W to 10000W.

[0007] According to an embodiment of the present disclosure, for the heating film, the length of the heating film is 250 mm to 450 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 1.2 g / cm 3 ~1.8 g / cm 3 under the condition that the power of the heating film is 30 W to 5000 W; the length of the heating film is 450 mm to 650 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 1.2 g / cm 3 ~1.8 g / cm 3 under the condition that the power of the heating film is 25 W to 10000 W; the length of the heating film is 250 mm to 450 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2 g / cm 3 under the condition that the power of the heating film is 10 W to 3400 W; and the length of the heating film is 450 mm to 650 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm 3 ~1.2 g / cm 3 under the condition that the power of the heating film is 10 W to 7000 W, and at least one of the above conditions is satisfied.

[0008] According to an embodiment of the present disclosure, the heating film has a sheet-like structure, the natural graphite and the graphene have a sheet-like structure, and the sheet-like extension plane of the heating film substantially coincides with the sheet-like extension plane of the natural graphite and / or the graphene.

[0009] According to an embodiment of the present disclosure, the heat generation temperature of the heating film is 500 °C to 1700 °C.

[0010] According to an embodiment of the present disclosure, the material of the heating film is graphite.

[0011] According to embodiments of the present disclosure, the heating film comprises a plurality of heating units arranged sequentially along its longitudinal direction, with adjacent heating units spaced apart and connected by connecting sections.

[0012] According to the embodiments of this disclosure, each heating unit is provided with a hollowed-out hole.

[0013] According to embodiments of the present disclosure, the heating film comprises a first heating section and a second heating section adjacent to each other in the longitudinal direction, the first heating section includes a plurality of connected heating units, the second heating section includes a plurality of adjacent heating units, the size of the heating units corresponding to the first heating section is smaller than the size of the heating units corresponding to the second heating section, and / or the first heating section and the second heating section are offset in the width direction of the heating film.

[0014] According to embodiments of the present disclosure, the heating film comprises a plurality of notches provided with gaps between them along its longitudinal direction.

[0015] According to embodiments of the present disclosure, each of the notches is defined by folding a portion of the heating film after it has separated from the rest.

[0016] In other aspects of the Disclosure, the Disclosure provides a method for manufacturing a heating film as described above. According to embodiments of the Disclosure, the method for manufacturing a heating film includes the steps of: providing natural graphite and intercalating it to obtain expandable graphite; expanding the expandable graphite to obtain expanded graphite; and rolling, performing a first heat treatment, and cutting the expanded graphite to obtain the heating film; or the method for manufacturing a heating film includes the steps of: uniformly mixing and dispersing graphene and an additive to obtain a dispersion; applying the dispersion to obtain a dispersion film; performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; and rolling and cutting the carbon-based primary film to obtain the heating film. As a result, a heating film made of graphite material manufactured from natural graphite or graphene has a high heating temperature, a fast heating rate, and is useful for achieving higher heating temperatures and higher heating efficiency. Furthermore, by employing natural graphite in the heating film of this disclosure, natural graphite ore is abundant among Earth's minerals, and at the same time, carbon-based film materials do not require high-temperature graphitization during the manufacturing process, nor do they require other manufacturing processes, allowing for continuous production and cost reduction. In short, carbon-based film materials have advantages such as a wide range of material sources, a simple manufacturing process, good product stability, and adjustable and easily adjustable performance parameters, resulting in significant benefits in terms of reducing product costs, increasing product reliability, and diversifying product types. If artificial graphite is adopted, it is necessary to set up a process flow for manufacturing artificial graphite, which significantly increases the cost and time of manufacturing heating films and reduces production efficiency. However, using graphene as a raw material is advantageous in obtaining heating films with a high carbon content, and moreover, the processing process is simple and mature, and the manufacturing cost is not high.

[0017] According to embodiments of the present disclosure, the conditions for the intercalation treatment are to intercalate the natural graphite with concentrated sulfuric acid and / or hydrogen peroxide to obtain the expandable graphite, and the conditions for the expansion treatment are to put the expandable graphite into an expansion furnace and expand it at a temperature of 850°C-1200°C to obtain the expanded graphite.

[0018] In further aspects of the present disclosure, the present disclosure provides a heating tube, and according to embodiments of the present disclosure, the heating tube comprises the heating film described above. This results in the heating tube having a high heating temperature, a fast heating rate, and a relatively concentrated heating area, thereby greatly increasing the heating efficiency of the heating tube. Those skilled in the art will understand that the heating tube has all the features and advantages of the heating film described above, and therefore will not be described further here.

[0019] In a further aspect of the present disclosure, the present disclosure provides an electrical heating device, which, according to an embodiment of the present disclosure, comprises a heating tube as described above. This results in the electrical heating device having a high heating temperature, a fast heating rate, and a relatively concentrated heating area, thereby significantly increasing the heating efficiency of the electrical heating device.

[0020] According to embodiments of this disclosure, the heating appliance is an electric oven, microwave oven, steam oven, electric kettle, electric blanket, electric heater, electric heater, bathroom heater, electric ceramic stove, or sterilization cabinet. [Brief explanation of the drawing]

[0021] The above and / or additional aspects and advantages of this disclosure will become apparent and easier to understand from the description of the embodiments combined with the following drawings. [Figure 1] This is a schematic diagram illustrating thermal radiation of the heating film in this disclosure. [Figure 2] This is a schematic diagram of thermal radiation in a conventional heating tube core. [Figure 3] This is a schematic diagram of the curve between the heating temperature and resistance of the heating film disclosed herein. [Figure 4]This is a schematic diagram of the curve between the thickness and resistance of the heating film of the present disclosure. [Figure 5] This is a schematic diagram of the structure of the heating film in the embodiments of the present disclosure. [Figure 6] This is a schematic diagram of the structure of a heating film in some other embodiments of the present disclosure. [Figure 7] This is a schematic diagram of the structure of a heating film in some other embodiments of the present disclosure. [Figure 8] This is a schematic diagram of the structure of a heating tube in some other embodiments of the present disclosure. [Figure 9] This is a schematic diagram of the structure of a heating tube in some other embodiments of the present disclosure. [Figure 10] This is a schematic diagram of the structure of a heating tube in some other embodiments of the present disclosure. [Figure 11] This is a schematic diagram of the structure of a heating film in some other embodiments of the present disclosure. [Modes for carrying out the invention]

[0022] The means of this disclosure will be interpreted in combination with the following examples. Those skilled in the art will understand that the following examples are used solely to illustrate this disclosure and should not be considered to limit the scope of this disclosure. Where no specific technique or conditions are shown in the examples, they should be carried out in accordance with the techniques or conditions described in the art literature or in accordance with the product specifications. Where the manufacturer of the reagents or equipment used is not indicated, they are conventional products available on the market.

[0023] The present disclosure will be explained below with reference to specific examples, and it should be noted that these examples are illustrative and do not limit the present disclosure in any way.

[0024] In one aspect of the present disclosure, the present disclosure provides a heating film. According to an embodiment of the present disclosure, the material of the heating film comprises natural graphite and / or graphene, the heating film has a thickness of 0.04 mm to 2 mm, for example, the thickness of the heating film is 0.04 mm, 0.08 mm, 0.1 mm, 0.2 mm, 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, 1.5 mm, 1.8 mm, 2.0 mm, etc., and the density of the heating film is 0.6 g / cm³ 3 ~1.8g / cm 3 For example, the density of the heating film is 0.6 g / cm³. 3 0.8 g / cm³ 3 , 1.0 g / cm³ 3 , 1.2 g / cm³ 3 1.4 g / cm³ 3 1.5 g / cm³ 3 1.6 g / cm³ 3 1.8 g / cm³ 3It satisfies at least one of the following conditions. As a result, heating films made of graphite material produced from natural graphite or graphene have a high heating temperature, a fast heating rate, and are useful in achieving higher heating temperatures and higher heating efficiency. Furthermore, by adopting natural graphite for the heating film of this disclosure, natural graphite ore is abundant among Earth's minerals, and at the same time, carbon-based film materials do not require high-temperature graphitization in the manufacturing process, do not require production through other processes, can be produced continuously, and costs can be reduced. In short, carbon-based film materials have advantages such as a wide range of material sources, a simple manufacturing process, good product stability, and performance parameters that can be adjusted as needed and are easy to adjust, which offers enormous advantages in terms of reducing product costs, increasing product reliability, and increasing the variety of products. Using artificial graphite necessitates setting up a process flow for manufacturing artificial graphite, which significantly increases the cost and time of manufacturing the heating film and reduces production efficiency. However, using graphene as a raw material is advantageous for obtaining heating films with a high carbon content, and the processing process is simple and mature, resulting in low manufacturing costs. Furthermore, the above heating film, when meeting the above conditions, can meet a wide range of power requirements. That is, by adjusting the thickness and density of the heating film as described above, heating films with different power values ​​can be obtained, not only for high-power heating films but also for highly efficient heating films. At the same time, the manufacturability of the heating film under the above conditions is good, meaning that the production yield is high and the lifespan meets the usage requirements.

[0025] In some embodiments of this disclosure, the material graphene may be graphene nanoplatelets, which refer to ultrathin graphene layered deposits having 10 or more carbon layers and a thickness in the range of 5-100 nanometers. Graphene nanoplatelets have good thermal conductivity and tensile strength, and are useful in improving the heat generation temperature and mechanical strength of the manufactured heating film.

[0026] According to some embodiments of this disclosure, the heating film has a sheet-like structure, the natural graphite and / or graphene used as raw materials for manufacturing the heating film also has a sheet-like structure, and the sheet-like extending plane of the heating film substantially coincides with the sheet-like extending plane of the graphite and / or graphene. As a result, as shown in Figure 1, when the sheet-like heating film 20 generates heat, the heat is mainly radiated along the direction perpendicular to the heating surface (i.e., the plane of the film), which is highly directional, concentrates the radiated heat, further improves the heating efficiency, and reduces heat loss. In the current prior art, referring to Figure 2, the heat radiation from the heating tube core 1 (e.g., a metal heating tube core or a quartz tube core) is emitted evenly to the surroundings and cannot be concentrated, which usually leads to wasted heat and reduces heating efficiency. In comparison, the heat radiation direction of the heating film of this disclosure is more concentrated, allowing for better directional heating of the object to be heated and improving heating efficiency. It is important to clarify that the term "approximately coincides" above means that the sheet-like extending plane of the heating film should roughly coincide with the sheet-like extending plane of graphite and / or graphene; it does not require that the two planes coincide perfectly or be perfectly parallel.

[0027] According to some embodiments of this disclosure, as described above, the material of the heating film manufactured from the raw material natural graphite and / or graphene is graphite, and therefore the heating film of this disclosure has a high heating temperature and a fast heating rate. The manufactured graphite is still in a sheet-like structure, and the planar extension direction of the sheet-like structure substantially coincides with the planar extension direction of the raw material natural graphite or graphene, so it can be said that the sheet-like extension plane of the heating film substantially coincides with the sheet-like extension plane of its material, graphite.

[0028] According to some embodiments of this disclosure, the carbon content of the heating film is 99% or more. This is advantageous in obtaining a heating film with a high carbon content, i.e., high purity and better performance.

[0029] According to several embodiments of this disclosure, the power of the heating film ranges from 15W to 10000W, for example, 15W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 4500W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc. This allows the heating film of this disclosure to effectively achieve heating at a wide range of different power levels, enabling not only ultra-low power heating but also ultra-high power heating, thus meeting the power usage requirements of the heating film under various different application conditions.

[0030] According to some embodiments of this disclosure, heating films made from natural graphite and / or graphene nanoplatelets further possess self-limiting temperature properties. Specifically, referring to Figure 3, the heating film has a critical temperature, and when the temperature of the heating film is below the critical temperature, the resistance of the heating film decreases as the temperature rises, and when the temperature of the heating film is above the critical temperature, the resistance of the heating film increases as the temperature rises. As a result, the heating film of this disclosure has a self-limiting temperature characteristic. Specifically, in the initial stage of heating (i.e., when the temperature of the heating film is below the critical temperature), the resistance of the heating film decreases as the temperature rises, the current increases, and the power of the heating film increases as the temperature rises. Therefore, at this stage, the heating film heats up rapidly. After the heating film's exothermic temperature reaches the critical temperature, the resistance of the heating film increases as the temperature rises, the current decreases, and the power of the heating film decreases as the temperature rises. Therefore, at this stage, the heating rate of the heating film slows down, and it gradually reaches the maximum exothermic temperature of the heating film. Due to the self-limiting temperature characteristic of the heating film, the heating rate in the temperature range below the critical temperature of the heating film can be accelerated, allowing the heating film to reach the target temperature as quickly as possible. At the same time, if the temperature is above the critical temperature, the problem of melting that occurs during the process of sustained heating can be reduced, thereby improving the reliability and stability of the heating film. It is important to explain that Figure 3 is simply a temperature-resistance curve diagram of a heating film in one embodiment, but the curve trend represents a schematic diagram of the temperature-resistance curve of the heating film according to this disclosure.

[0031] According to some embodiments of this disclosure, as shown in Figure 4, the resistance characteristics (equal density) of the carbon-based heating film gradually decrease with increasing resistance thickness, with greater thickness resulting in lower resistance and less thickness resulting in higher resistance. Based on this, in this disclosure, heating films with various different power values ​​can be obtained under the above density and thickness conditions. Furthermore, with different parameters such as different thicknesses, density levels, and lengths of the heating film, the heating film will have different power values, specifically as follows.

[0032] According to some embodiments of this disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 250 mm to 450 mm (e.g., 250 mm, 280 mm, 300 mm, 320 mm, 350 mm, 370 mm, 400 mm, 420 mm, 450 mm, etc.), the width of the heating film is 6 mm to 10 mm (e.g., 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.), and the density of the heating film is 1.2 g / cm³. 3 ~1.8g / cm 3 (For example, 1.2 g / cm³) 3 1.3 g / cm³ 3 1.4 g / cm³ 3 1.5 g / cm³ 3 1.6 g / cm³ 3 1.7 g / cm³ 3 1.8 g / cm³ 3 The heating film may have a power of 30W to 5000W, for example, 30W, 40W, 50W, 80W, 100W, 150W, 200W, 300W, 400W, 800W, 1000W, 1300W, 1500W, 1800W, 2000W, 2300W, 2500W, 2800W, 3000W, 3200W, 3500W, 3800W, 4000W, 4200W, 4500W, 4800W, 5000W, etc. Under the above length, thickness, and density conditions, the heating film can have a power of 30W to 5000W, and by adjusting the power, it is possible to reach an appropriate heating temperature and obtain a heating film that meets the demand.

[0033] According to some embodiments of this disclosure, the heating film has a thickness of 0.04 mm to 2 mm, a length of 450 mm to 650 mm (e.g., 450 mm, 500 mm, 520 mm, 550 mm, 580 mm, 600 mm, 630 mm, 650 mm, etc.), a width of 6 mm to 10 mm (e.g., 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, etc.), and a density of 1.2 g / cm³. 3 ~1.8g / cm 3 (For example, 1.2 g / cm³) 3 1.3 g / cm³ 3 1.4 g / cm³ 3 1.5 g / cm³ 3 1.6 g / cm³ 3 1.7 g / cm³ 3 1.8 g / cm³ 3 The heating film may have a power of 25W to 10000W, for example, 25W, 30W, 40W, 50W, 60W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 4500W, 5000W, 6000W, 7000W, 8000W, 9000W, 10000W, etc. Under the above length, thickness, and density conditions, the heating film can have a power of 25W to 5000W, and by adjusting the power, it is possible to reach an appropriate heating temperature and obtain a heating film that meets the demand.

[0034] According to some embodiments of this disclosure, the heating film has a thickness of 0.04 mm to 2 mm, a length of 250 mm to 450 mm, a width of 6 mm to 10 mm, and a density of 0.6 g / cm³. 3 ~1.2g / cm 3 (For example, 0.6 g / cm³) 3 , 0.7 g / cm³ 3 0.8 g / cm³ 3 , 0.9 g / cm³ 3 , 1.0 g / cm³ 3 , 1.1 g / cm³ 3 , 1.2 g / cm³ 3(etc.) The power of the heating film may be 10W to 3400W, for example, 10W, 15W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 3400W, etc. Under the above length, thickness, and density conditions, the heating film can have a power of 10W to 5000W, and by adjusting the power, it is possible to reach an appropriate heating temperature and obtain a heating film that meets the demand.

[0035] According to some embodiments of this disclosure, the thickness of the heating film is 0.04 mm to 2 mm, the length of the heating film is 450 mm to 650 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm³. 3 ~1.2g / cm 3 (For example, 0.6 g / cm³) 3 , 0.7 g / cm³ 3 0.8 g / cm³ 3 , 0.9 g / cm³ 3 , 1.0 g / cm³ 3 , 1.1 g / cm³ 3 , 1.2 g / cm³ 3 The heating film may have a power of 10W to 7000W, for example, 10W, 20W, 40W, 50W, 70W, 100W, 150W, 300W, 500W, 800W, 1000W, 1500W, 3000W, 3400W, 4000W, 4500W, 5000W, 5400W, 6000W, 6500W, 7000W, etc. Under the above length, thickness, and density conditions, the heating film can have a power of 10W to 7000W, and by adjusting the power, it is possible to reach an appropriate heating temperature and obtain a heating film that meets the demand.

[0036] According to some embodiments of this disclosure, the thermal diffusion coefficient of the heating film is 50 m 2 / s~450m 2 / s, for example 50m 2 / s, 80m 2 / s, 100m 2 / s, 130m 2 / s, 150m 2 / s, 280m2 / s, 300m 2 / s, 320m 2 / s, 350m 2 / s, 370m 2 / s, 400m 2 / s, 420m 2 These coefficients of thermal diffusivity include 450 m / s and 450 m / s. Due to the above thermal diffusivity, the heat from the heating film is transferred into the heating chamber at an appropriate rate, concentrating the heat generated by the heating film mainly on the object to be heated. In this way, not only is an excellent heating rate ensured, but the heat is not transferred too quickly, preventing large heat losses. Furthermore, the above thermal diffusivity contributes to extending the service life of the heating film and improving its manufacturability.

[0037] According to some embodiments of this disclosure, the heating temperature of the heating film is 500°C to 1700°C, for example, 500°C, 550°C, 600°C, 700°C, 800°C, 900°C, 1000°C, 1100°C, 1200°C, 1300°C, 1400°C, 1500°C, 1600°C, 1700°C, etc. Thus, the heating temperature of the heating film of this disclosure can reach a maximum of 1700°C, and moreover, those skilled in the art will see that the maximum heating temperature of the heating film can be flexibly adjusted by adjusting the density and / or thickness of the heating film, etc., according to the specific application requirements of the heating film, and furthermore, it is possible to meet a wider range of application heating requirements for the heating film and obtain heating films of various different power levels, such as ultra-low power heating films or ultra-high power heating films.

[0038] In the embodiments of this disclosure, the specific cutting types of the heating film can be varied, and those skilled in the art can flexibly design the cutting types of the heating film according to the requirements of the actual conditions, such as the resistance and power of the heating film. Several cutting types of the heating film will be described below in some specific embodiments of this disclosure.

[0039] In some embodiments of the present disclosure, referring to FIG. 5, the heating film includes heating units 01 sequentially arranged along a plurality of longitudinal directions. Adjacent heating units 01 are provided with a gap and are connected by a connection section 02. Thus, it can be seen that the heating film of the present disclosure can be cut into structures of various different cutting types to meet the demands of different uses. In some embodiments of the present disclosure, referring to FIG. 5, the outer peripheral wall of the heating unit is formed in an oval or polygonal shape.

[0040] In some embodiments of the present disclosure, referring to (b), (c), and (i) in FIG. 5, each heating unit 01 is provided with a punched hole 03. By providing the punched hole, the heat dissipation rate of the heating film can be accelerated, and the heating rate of the heated object can be accelerated.

[0041] In some embodiments of the present disclosure, referring to FIG. 6, the heating film includes a first heating section S2 and a second heating section S1 adjacent in the longitudinal direction. The first heating section S2 includes a plurality of connected heating units 01, the second heating section S1 includes a plurality of adjacent heating units 01, the size of the heating unit 01 corresponding to the first heating section S2 is smaller than the size of the heating unit 01 corresponding to the second heating section S1. For example, as shown in (a) in FIG. 6, the length of the heating unit 01 corresponding to the first heating section S2 is the same as the length of the heating unit 01 corresponding to the second heating section S1, but the widths d2 and d1 of the two are not equal, and d2 < d1. For example, as shown in (b) and (c) in FIG. 6, the width of the heating unit 01 corresponding to the first heating section S2 is the same as the width of the heating unit 01 corresponding to the second heating section S1, but the lengths d2 and d1 of the two are not equal, and d2 < d1. Thus, the diversification of the heating film structure can be realized.

[0042] In some embodiments of the present disclosure, referring to FIG. 7, the first heating section and the second heating section are provided offset in the width direction of the heating film. Thus, the diversification of the heating film structure can be realized.

[0043] In some embodiments of this disclosure, referring to Figures 5(d), (e), (f), (h), (i), and (j), the heating film has a plurality of notches spaced apart along its longitudinal direction. This allows for diversification of the heating film structure. Furthermore, in some embodiments of this disclosure, referring to Figure 5(i), each notch is defined by folding a portion of the heating film after it has separated from the rest.

[0044] In some embodiments, as shown in Figure 11, the same heating film may include multiple different cutting types, or the same cutting type with a non-uniform density distribution.

[0045] In other aspects of this disclosure, the disclosure provides a method for manufacturing the heating film described above. According to the embodiments of this disclosure, the method for manufacturing the heating film is manufactured from natural graphite and graphene, respectively, and the specific manufacturing steps are as follows.

[0046] In some embodiments, a method for producing a heating film using natural graphite includes the following steps:

[0047] In S100, natural graphite is provided and subjected to intercalation treatment to obtain expandable graphite.

[0048] In this disclosure, using natural graphite eliminates the need for other manufacturing processes, further reducing the process flow for manufacturing the heating film and lowering costs. Using artificial graphite requires setting up an additional process flow for manufacturing the artificial graphite, which significantly increases the cost and time of manufacturing the heating film and reduces production efficiency. Furthermore, using natural flake graphite results in a layered structure rather than a single-layer structure, and the graphite in the manufactured heating film also has a layered structure, which enhances the concentrated heating effect of the heating film. Moreover, natural flake graphite is abundant in earth minerals, and carbon-based heating film materials do not require high-temperature graphitization during the manufacturing process, allowing for continuous production. This further improves production efficiency, reduces production costs, and enhances production safety because high-temperature graphitization is not required.

[0049] Furthermore, natural flake graphite is abundant among Earth's minerals, and the heating film material of this disclosure does not require high-temperature graphitization during the manufacturing process, allowing for continuous production. Moreover, it further improves production efficiency, reduces production costs, and enhances production safety by eliminating the need for high-temperature graphitization.

[0050] In some examples, the specific method of intercalation treatment may involve intercalating natural flake graphite with an oxide such as concentrated sulfuric acid and / or hydrogen peroxide to obtain expansive graphite.

[0051] In S200, expandable graphite is subjected to an expansion treatment to obtain expanded graphite.

[0052] In several examples, after the expandable graphite enters the expansion furnace, it rapidly expands after a momentary period of high temperature, forming graphite worms, or expanded graphite. The expansion ratio of the expandable graphite may be 30 to 400 times after the expansion treatment. During the expansion treatment process, the expansion temperature is 850°C to 1200°C, and the expansion time is 0.7 s to 1.3 s.

[0053] In S300, expanded graphite is rolled, subjected to a first heat treatment, and cut to obtain a heating film. Different types of cutting for the heating films can be seen in Figures 5 to 7, and the characteristics of the specific cutting types are consistent with the requirements described above, so they will not be explained further here.

[0054] The specific method for the first heat treatment is not particularly required, and those skilled in the art can employ specific heat treatment methods in the prior art that involve deoxygenating graphite oxide to obtain graphite.

[0055] In this way, the thickness and density of the heating film can be controlled by rolling the expanded graphite. The thickness and density of the heating film are as described above and will not be explained further here.

[0056] According to the embodiments of this disclosure, a heating film made of graphite material produced from natural graphite has a high heating temperature and a fast heating rate, which helps to achieve higher heating temperatures and higher heating efficiency. Furthermore, by using natural graphite in the heating film of this disclosure, natural graphite ore is abundant among Earth's minerals, and the carbon-based film material does not require high-temperature graphitization during the manufacturing process, nor does it require other manufacturing processes, allowing for continuous production and cost reduction. In short, carbon-based film material has advantages such as a wide range of material sources, a simple manufacturing process, good product stability, and adjustable and easily adjustable performance parameters, resulting in significant advantages in terms of reducing product costs, increasing product reliability, and diversifying product types. If artificial graphite is used, it is necessary to set up an additional process to manufacture the artificial graphite, which significantly increases the cost and time of manufacturing the heating film and reduces production efficiency. However, heating films manufactured using natural graphite as a material have a fast heating rate, a high heating temperature, and a rapid temperature rise rate. Furthermore, heating films with the above density and thickness can meet the different power requirements of heating films, and the carbon-based heating films of this disclosure have good manufacturability, i.e., high production yield and long service life.

[0057] In some examples, a method for producing a heating film from graphene includes the following steps:

[0058] In S400, graphene and additives are uniformly mixed and dispersed to obtain a dispersion.

[0059] In several examples, the graphene used was graphene nanoplatelets, with a planar size of 1 μm-100 μm and a specific surface area of ​​30 m². 2 / g-800m 2 The graphene nanoplatelets meeting the above requirements are easily dispersed uniformly at a density of / g.

[0060] In some examples, the additive includes at least one of carboxymethylcellulose, polyvinyl alcohol, polyethylene glycol, polyacrylic acid, and aqueous polyurethane, and the addition of the above additives can effectively increase the film-forming ability of graphene nanoplatelets.

[0061] Furthermore, based on the total mass of the dispersion, the mass of the additive is 5% or less, for example, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5%, etc. The low amount of additive used does not affect the good performance of the manufactured heating film.

[0062] In S500, a dispersion is applied to obtain a dispersion film.

[0063] In some embodiments, the specific method of coating is not particularly required, and those skilled in the art can flexibly select an appropriate coating method according to their actual needs, such as spin coating or spray coating.

[0064] In S600, a second heat treatment is performed on the dispersion film to obtain a carbon-based primary film.

[0065] In this step, graphene is deoxygenated by a second heat treatment to obtain graphite material. The heat treatment can be carried out under vacuum or inert atmosphere, and the temperature of the second heat treatment is 1500°C-3000°C. By the above method, graphite with a high carbon content can be obtained, for example, the carbon content can reach 99% or more.

[0066] In S700, a carbon-based primary film is rolled and cut to obtain a heating film. The cutting process yields heating films of specific cut types; specific cut types can be seen in Figures 5, 6, and 7. The characteristics of these specific cut types are consistent with the requirements described above, and therefore will not be explained further here.

[0067] According to the embodiments of this disclosure, since graphene is used as a raw material, it is useful for obtaining heating films with a high carbon content, and the processing process is simple, mature, and not expensive to manufacture. Furthermore, the graphene nanoplatelets used have good thermal conductivity and tensile strength, and are useful for improving the heating temperature and mechanical strength of the manufactured heating film.

[0068] In further aspects of the present disclosure, the present disclosure provides a heating tube, and according to embodiments of the present disclosure, the heating tube comprises the heating film described above. This results in the heating tube having a high heating temperature, a fast heating rate, and a relatively concentrated heating area, thereby greatly increasing the heating efficiency of the heating tube. Those skilled in the art will understand that the heating tube has all the features and advantages of the heating film described above, and therefore will not be described further here.

[0069] In some embodiments, referring to Figures 8 (where S refers to a local cross-sectional view of the casing), 9, and 10, the heating tube further comprises a casing 10, the heating film 20 is placed on the casing 10, terminals 21 are provided at both ends of the heating film 20, and the casing may be a quartz glass tube or the like.

[0070] In a further aspect of the present disclosure, the present disclosure provides an electrical heating device, which, according to an embodiment of the present disclosure, comprises a heating tube as described above. This results in the electrical heating device having a high heating temperature, a fast heating rate, and a relatively concentrated heating area, thereby significantly increasing the heating efficiency of the electrical heating device.

[0071] According to embodiments of this disclosure, the heating appliance is an electric oven, microwave oven, steam oven, electric kettle, electric blanket, electric heater, electric heater, bathroom heater, electric ceramic stove, or sterilization cabinet.

[0072] Those skilled in the art will understand that, in addition to the heating tube, an electrical heating device includes structures or components necessary for an electrical heating device, and, taking an electric oven as an example, it includes necessary structures or components such as a housing, heating space, base, and plug in addition to the heating tube.

[0073] Examples

[0074] Examples 1-7, Comparative Examples 1-2

[0075] A heating film is manufactured using natural flake graphite, and the heating film has a density of 1.8 g / cm³. 3 The length is 300 mm, the width is 8 mm, and the cutting type is (a) in Figure 5. The density, power, and performance tests of the heating film are shown in Table 1 below. As can be seen from Table 1, under conditions where the density is constant, the power of the heating film increases with increasing thickness, but whether the thickness is large or small affects the manufacturability of the heating film. In addition, all heating films in the examples have high heating temperatures.

[0076] [Table 1]

[0077] Examples 8-14, Comparative Examples 3-4

[0078] A heating film is manufactured using natural flake graphite, and the heating film has a density of 1.8 g / cm³. 3 The length is 600 mm, the width is 8 mm, and the cutting type is (a) in Figure 5. The density, power, and performance tests of the heating film are shown in Table 2 below. As can be seen from Table 2, under conditions where the density is constant, the power of the heating film increases with increasing thickness, but whether the thickness is large or small affects the manufacturability of the heating film. In addition, all heating films in the examples have high heating temperatures.

[0079] [Table 2]

[0080] Examples 15-21, Comparative Examples 5-6 A heating film is manufactured using natural flake graphite, and the heating film has a density of 0.6 g / cm³. 3 The length is 300 mm and the width is 8 mm, and the cutting type is (a) in Figure 5. The density, power, and performance tests of the heating film are shown in Table 3 below. As can be seen from Table 3, under conditions where the density is constant, the power of the heating film increases with increasing thickness, but whether the thickness is large or small affects the manufacturability of the heating film. In addition, all heating films in the examples have high heating temperatures.

[0081] [Table 3]

[0082] Examples 22-28, Comparative Examples 7-8

[0083] A heating film is manufactured using natural flake graphite, and the heating film has a density of 0.6 g / cm³. 3The length is 600 mm and the width is 8 mm, and the cutting type is (a) in Figure 5. The density, power, and performance tests of the heating film are shown in Table 4 below. As can be seen from Table 4, under conditions where the density is constant, the power of the heating film increases with increasing thickness, but whether the thickness is large or small affects the manufacturability of the heating film. In addition, all heating films in the examples have high heating temperatures.

[0084] [Table 4]

[0085] Examples 29-35, Comparative Examples 9-10

[0086] A heating film is manufactured using natural flake graphite, and the heating film has a density of 1.0 g / cm³. 3 The length is 600 mm, the width is 8 mm, and the cutting type is (a) in Figure 5. The density, power, and performance tests of the heating film are shown in Table 5 below. As can be seen from Table 5, under conditions where the density is constant, the power of the heating film increases with increasing thickness, but whether the thickness is large or small affects the manufacturability of the heating film. In addition, all heating films in the examples have high heating temperatures.

[0087] [Table 5]

[0088] [Table 6]

[0089] As can be seen from the test data in Tables 1 to 6 above, the heating film of this disclosure has a thickness of 0.04 mm to 2 mm and a density of 0.6 g / cm³. 3 ~1.8g / cm 3If the following conditions are met, various different ultra-low power or ultra-high power heating films can be manufactured to obtain different heating temperatures and be used to meet various different application requirements in the market. Also, under certain conditions, the heating temperature gradually decreases as the thickness of the heating film increases.

[0090] The method for determining manufacturability is as follows: A heating film is considered "good" if it has good flexibility, a certain degree of rigidity, is easy to release and transport, has high processing and manufacturing efficiency, is resistant to stretching and breakage, and has a normal production and manufacturing acceptance rate of 99% or higher; otherwise, it is considered "poor".

[0091] The above lifespan test method is as follows: Apply 1.1 times the rated voltage to the heating film, and after the continuous operating time reaches 525 hours, (1) there are no cracks, notches, or deformation in the heating tube, (2) there is no breakage or bending deformation in the heating film, and the power variation meets the design requirements of the drawing, (3) insulation resistance: test the distance between the charged component (terminal) and the uncharged component (tube wall) of the heating tube with a DC500V insulation resistance meter, and the test resistance is ≥ 500MΩ (DC500V), and (4) insulation strength: apply a voltage of 1800VAC / 3S / 5mA between the charged component (terminal) and the uncharged component (tube wall) of the heating tube, and if there is no flashing and no destructive phenomena, it is considered acceptable.

[0092] Example 43

[0093] The disclosed data has a thickness of 1.0 mm and a density of 1.2 g / cm³. 3 A heating film (cut type is (a) in Figure 5) was fabricated into a heating tube, and this heating tube, halogen tube, quartz tube, and metal tube were each used in the same oven, with the power of all heating tubes set to 600W, and the time required for each heating tube to reach 200°C in the oven was tested. The test results are shown in Table 7. In addition, heating tubes made from heating films of different thicknesses and densities were each set to 600W, and the time required for the oven to reach 200°C was tested. The test results are shown in Table 8.

[0094] [Table 7]

[0095] [Table 8]

[0096] As can be seen from this, the heating tube made of the heating film of this disclosure can reach the required heating temperature in a short time, that is, the heating film of this disclosure has a fast heating rate and also has good heating efficiency.

[0097] Examples 44-45, Comparative Examples 13-14

[0098] A heating film is manufactured using natural flake graphite. The heating film has a thickness of 1.0 mm and a density of 1.2 g / cm³. 3 The film has a width of 8 mm, and the cutting type is (a) in Figure 5. The thermal diffusivity coefficient and performance tests of the heating film in different embodiments are shown in Table 9 below. The heating film of each embodiment was made into a heating tube, and the power of all heating tubes was set to 600 W. The time required for each heating tube to reach 200°C in the oven was tested. The test results are shown in Table 9.

[0099] [Table 9]

[0100] As can be seen from the above test results, the thermal diffusion coefficient of the heating film disclosed herein is 50 m 2 / s~450m 2 A thermal diffusion coefficient of 450 m² is required. 2 If the value is greater than / s, the heating time will increase accordingly, and the density of the heating film will also increase, making it more difficult to implement in the process and increasing the difficulty of the process.

[0101] Furthermore, the terms “first” and “second” are used solely for descriptive purposes and are not intended to indicate or suggest the number of technical features of relative importance. Therefore, features limited by “first” and “second” may include one or more such features, either explicitly or implicitly. In this description, “multiple” means two or more unless otherwise specified.

[0102] In this specification, any reference to terms such as “one embodiment,” “several embodiments,” “example,” “specific example,” or “several examples” means that a particular feature, structure, material, or property described with reference to such embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the general expressions of the above terms do not necessarily apply to the same embodiment or example. In addition, any particular feature, structure, material, or property described may be incorporated in an appropriate manner in any one or more embodiments or examples. Furthermore, those skilled in the art can combine and combine the various embodiments or examples and the features relating to the various embodiments or examples described herein without contradiction.

[0103] While examples of the present disclosure have been presented and described, these examples are illustrative and should not be understood as limiting the disclosure. Those skilled in the art will understand that various changes, modifications, substitutions, and variations are possible within the scope of the present disclosure. (Cross-reference of related applications)

[0104] This disclosure claims priority rights to the Chinese patent application no. 202410119728.X, proposed on 26 January 2024, which is incorporated herein by reference in its entirety.

Claims

1. A heating film, wherein the material of the heating film comprises natural graphite and / or graphene, and the heating film is The conditions are that the thickness of the heating film is 0.04 mm to 2 mm, and The density of the aforementioned heating film is 0.6 g / cm³. ３ ~1.8 g / cm ３ A heating film that satisfies at least one of the following conditions.

2. The heating film according to claim 1, wherein the carbon content of the heating film is 99% or more.

3. The heating film according to claim 1, wherein the power of the heating film is 15W to 10000W.

4. The aforementioned heating film is The heating film has a length of 250 mm to 450 mm, a width of 6 mm to 10 mm, and a density of 1.2 g / cm³. ３ ~1.8 g / cm ３ The conditions are that the power of the heating film is 30W to 5000W, The heating film has a length of 450 mm to 650 mm, a width of 6 mm to 10 mm, and a density of 1.2 g / cm³. ３ ~1.8 g / cm ３ The conditions are that the power of the heating film is 25W to 10000W, The heating film has a length of 250 mm to 450 mm, a width of 6 mm to 10 mm, and a density of 0.6 g / cm³. ３ ~1.2 g / cm ３ The conditions are that the power of the heating film is 10W to 3400W, and The length of the heating film is 450 mm to 650 mm, the width of the heating film is 6 mm to 10 mm, and the density of the heating film is 0.6 g / cm ３ ~1.2 g / cm ３ and the heating film satisfies one of the conditions that the power of the heating film is 10 W to 7000 W. The heating film according to claim 3.

5. The heating film according to claim 1, wherein the heating film has a sheet-like structure, the natural graphite and the graphene have sheet-like structures, and the sheet-like extending plane of the heating film substantially coincides with the sheet-like extending plane of the natural graphite and / or the graphene.

6. The heating film according to claim 1, wherein the heating temperature of the heating film is 500°C to 1700°C.

7. The heating film according to claim 1, wherein the material of the heating film is graphite.

8. The heating film according to claim 1, wherein the heating film comprises a plurality of heating units arranged sequentially along the longitudinal direction, and adjacent heating units are provided with gaps between them and connected by connecting sections.

9. The heating film according to claim 8, wherein each of the heating units is provided with a cutout hole.

10. The heating film comprises a first heating section and a second heating section adjacent to each other in the longitudinal direction, the first heating section includes a plurality of connected heating units, the second heating section includes a plurality of adjacent heating units, the size of the heating unit corresponding to the first heating section is smaller than the size of the heating unit corresponding to the second heating section, and / or The heating film according to claim 8, wherein the first heating section and the second heating section are provided offset in the width direction of the heating film.

11. The heating film according to claim 8, wherein the heating film comprises a plurality of notches provided with gaps along its longitudinal direction.

12. The heating film according to claim 11, wherein each of the aforementioned notches is defined by folding a portion of the heating film after it has separated from the rest.

13. A method for producing a heating film according to any one of claims 1 to 12, The steps include providing natural graphite and intercalating the natural graphite to obtain expandable graphite, The steps include: expansive treatment of the aforementioned expandable graphite to obtain expanded graphite; The process includes the steps of rolling, first heat treatment, and cutting the expanded graphite to obtain the heating film, or The steps include: uniformly mixing and dispersing the graphene and additive to obtain a dispersion; The steps include applying the dispersion to obtain a dispersion film, The steps include: performing a second heat treatment on the dispersion film to obtain a carbon-based primary film; A method for producing a heating film, comprising the steps of rolling and cutting the carbon-based primary film to obtain the heating film.

14. The conditions for the intercalation treatment are to intercalate the natural graphite with concentrated sulfuric acid and / or hydrogen peroxide to obtain the expandable graphite. The method according to claim 13, wherein the conditions for the expansion treatment are to introduce the expandable graphite into an expansion furnace and expand it at a temperature of 850°C to 1200°C to obtain the expanded graphite.

15. A heating tube comprising a heating film according to any one of claims 1 to 12.

16. An electrical heating device comprising the heating tube described in claim 15.

17. The heating appliance according to claim 16, wherein the heating appliance is an electric oven, microwave oven, steam oven, electric kettle, electric blanket, electric heater, electric heater, bathroom heater, electric ceramic stove, or sterilization cabinet.

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