Temperature-controllable electric heating compound and preparation method thereof

Abstract

The invention relates to the technical field of electric heating materials, in particular to a temperature-controllable electric heating compound and a preparation method thereof. The invention provides a temperature-controllable electric heating compound which comprises a composite heating layer, a packaging insulating layer and a copper foil electrode clamped between the composite heating layer and the packaging insulating layer, a matrix insulating layer is arranged below the composite heating layer, and a series of regularly arranged circular holes are formed in the composite heating layer; and the packaging insulating layer packages the copper foil electrode and the composite heating layer on the substrate insulating layer. The composite heating layer is provided with a series of regularly arranged circular holes, so that the temperature distribution is more uniform, and the accuracy of temperature control can be improved. The supporting performance, the fatigue resistance and the bending resistance are achieved, and the risk of electric breakdown is reduced. Therefore, the method has a wide market application prospect. Meanwhile, the invention further provides a preparation method of the temperature-controllable electric heating compound, and the preparation method is simple in step, convenient to operate and suitable for large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of electric heating materials, and in particular to a temperature-controllable electric heating composite and a preparation method thereof. Background Art

[0002] With the increasing demand for electric heating technology in industrial and civil fields, such as building heating, soil heating, snow and ice melting of power equipment and airport runways, pipeline and tank insulation projects, etc., there is also a wide range of demand in temperature-sensitive components, intelligent low-temperature start-up, communications and automobiles. At the same time, countries around the world currently attach great importance to the environment, and all walks of life have higher and higher requirements for energy conservation and emission reduction. In order to adapt to energy conservation and emission reduction and fully meet users' requirements for low cost and high safety, higher requirements are put forward for electric heating or building heating technology.

[0003] However, when the floor temperature continues to rise to a preset temperature after the general electric heating composite is energized, if there is a carpet or other large covering on the floor far away from the temperature sensor, the covered area cannot dissipate heat well, resulting in temperature superposition, causing local overtemperature, burning the floor or the covering on the floor, and even a fire in severe cases, endangering life and property safety.

[0004] Therefore, a temperature-controllable electric heating composite is needed to effectively solve the temperature superposition phenomenon that may occur in the electric heating technology system, and eliminate the safety hazards of local overheating or system temperature out of control during use. It is also safer and energy-saving, and is also convenient for large-scale production, paving the way for large-scale and high-speed development of the electric heating and electric floor heating industries. Summary of the invention

[0005] In order to address the deficiencies in the prior art, the present invention provides a controllable temperature electrothermal composite and a preparation method thereof. By designing a series of regular circular holes on the surface, the temperature distribution is made more uniform, which helps to improve the accuracy of temperature control, improve the overall supporting performance, fatigue resistance and bending resistance, and reduce the risk of electrical breakdown. To solve the above problems, the technical solution of the present invention is: In the first aspect, the present invention provides a controllable temperature electric heating composite, comprising a composite heating layer, an encapsulation insulating layer, and a copper foil electrode sandwiched between the composite heating layer and the encapsulation insulating layer, a base insulating layer is provided under the composite heating layer, and a series of regularly arranged circular holes are provided on the composite heating layer; the encapsulation insulating layer encapsulates the copper foil electrode and the composite heating layer on the base insulating layer.

[0006] As a further improvement of the present invention, the materials of the base insulating layer and the encapsulating insulating layer are one or more of epoxy resin, polyester, polyurethane, silicone resin, polyimide alkyd resin, polyimide, polybutadiene, polystyrene, polypropylene, polycarbonate, polytetrafluoroethylene and silicone rubber.

[0007] As a further improvement of the present invention, the composite heating layer is composed of a high molecular polymer, an electric heating material and an organic solvent.

[0008] As a further improvement of the present invention, the electrothermal material is at least one of a carbon material and a conductive metal material.

[0009] As a further improvement of the present invention, the high molecular polymer is at least one of thermoplastic polyurethane, polyvinylidene fluoride, epoxy resin, polyacrylonitrile and ABS resin.

[0010] As a further improvement of the present invention, the solvent is one or more of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like.

[0011] As a further improvement of the present invention, the circular holes have a diameter of 5 to 20 mm, and the spacing between each two adjacent holes is 5 to 20 mm.

[0012] As a further improvement of the present invention, the distribution of the regular circular holes includes a square arrangement, a spiral arrangement or a random arrangement.

[0013] In a second aspect, the present invention provides a method for preparing a temperature-controllable electrothermal composite, characterized in that the method comprises the following steps: S1, dissolving a high molecular polymer in an organic solvent, and stirring under heating conditions to prepare a high molecular polymer glue; S2, adding the electric heating material to the high molecular polymer glue, and stirring to fully mix the electric heating material with the high molecular polymer glue to form an electric heating composite slurry; S3, using a slurry scraping method to evenly apply the electric heating composite slurry on the surface of the substrate insulation layer, and forming a composite heating layer after curing; S4. Punch out corresponding circular holes on the surface of the composite heating layer with a punch of corresponding size; S5. Placing the copper electrode on the surface of the prepared composite heating layer, and encapsulating the encapsulating insulating layer to obtain an electric heating composite of a "sandwich" structure of a base insulating layer - a composite heating layer - an encapsulating insulating layer.

[0014] As a further improvement of the present invention, the heating temperature range in S1 is 60-150°C.

[0015] As a further improvement of the present invention, the curing temperature range in S3 is 60-150°C.

[0016] Compared with the prior art, the temperature-controllable electrothermal composite provided by the present invention has the following beneficial effects: In the present invention, the electric thermal composite of the base insulation layer-composite heating layer-encapsulation insulation layer in a "sandwich" structure is obtained by encapsulating the encapsulation insulation layer. Due to the use of a series of regularly arranged circular holes, the surface area of ​​the electric thermal composite is effectively controlled, thereby controlling the heating temperature of the electric thermal composite. At the same time, the regular arrangement of the circular holes allows the heat to be more evenly spread to the surface of the electric thermal composite, thereby improving the temperature uniformity of the entire electric thermal composite. This helps to avoid the problem of excessively high or low local temperatures on the surface of the electric thermal composite, and improves the accuracy and stability of temperature control. The regular arrangement of circular holes not only improves the heat dissipation effect, but also increases the flexibility and plasticity of the electric heating film, making it more suitable for application scenarios of different shapes and sizes.

[0017] Furthermore, the preparation method of the temperature-controllable electrothermal composite of the present invention is simple, safe to operate and low in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the structure of the temperature-controllable electrothermal composite of the present invention; Figure 2 This is the electrothermal curve of the temperature-controllable electrothermal composite in Example 1 of the present invention.

[0019] In the accompanying drawings, the components represented by the reference numerals are listed as follows: 1. Encapsulation insulation layer; 2. Copper foil electrode; 3. Composite heating layer; 4. Base insulation layer. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0021] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0022] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0023] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0024] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an", "the" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0025] The weight of the relevant components mentioned in the embodiment description of the present application can not only refer to the specific content of each component, but also indicate the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the embodiment description of the present application, it is within the scope disclosed in the embodiment description of the present application. Specifically, the mass in the embodiment description of the present application can be a mass unit known in the chemical industry such as µg, mg, g, kg, etc.

[0026] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0027] The first object of the present invention is to provide a temperature-controllable electrothermal composite, such as Figure 1 As shown, it includes a composite heating layer 3 and an encapsulating insulating layer 1, and a copper foil electrode 2 clamped between the composite heating layer 3 and the encapsulating insulating layer 1, and a base insulating layer 4 is provided under the composite heating layer 3, and the composite heating layer 3 is composed of a high molecular polymer, an electric heating material and an organic solvent.

[0028] The electric heating composite consists of a composite heating layer 3, an encapsulation insulating layer 1, a copper foil electrode 2 and a base insulating layer 4. The composite heating layer 3 is located between the copper foil electrode 2 and the encapsulation insulating layer 1, while the base insulating layer 4 is arranged below the composite heating layer 3 to provide additional insulation protection. Working principle: When current passes through the copper foil electrode 2, it enters the composite heating layer 3. The electric heating material in the composite heating layer 3 (such as electric heating wire, electric heating film or electric heating powder, etc., the specific material is not clear but generally has good electric heat conversion performance) converts electrical energy into thermal energy. The high molecular polymer and organic solvent play the role of supporting and dispersing the electric heating material in the composite heating layer, and may also contribute to the uniform distribution of thermal energy. The encapsulation insulating layer 1 and the base insulating layer 4 ensure the electrical safety of the electric heating composite during operation and prevent current leakage and short circuit.

[0029] The temperature control mechanism is: Although the specific temperature control mechanism is not described in detail, temperature control can usually be achieved by adjusting the current, changing the type or content of the electric heating material, adjusting the thickness of the composite heating layer, etc. Possible temperature control methods also include using temperature sensors and controllers to monitor and adjust the temperature of the electric heating composite in real time.

[0030] The electrothermal material converts electrical energy directly into thermal energy, reducing energy loss. By precisely controlling the distribution of current and electrothermal materials, efficient thermal energy utilization can be achieved. The encapsulation insulation layer 1 and the base insulation layer 4 provide double insulation protection, reducing electrical safety risks. Possible temperature control mechanisms help prevent safety hazards such as overheating and fire. The electrothermal composite can be customized according to specific needs, such as changing the size, shape and type of electrothermal material. Using electrothermal materials as heat sources reduces fossil fuel consumption and environmental pollution. The recyclability of materials such as high molecular polymers and organic solvents helps to achieve the recycling of resources.

[0031] Preferably, the composite heating layer 3 has a series of regularly arranged circular holes.

[0032] The temperature-controllable electrothermal composite of the present invention significantly improves the performance of the electrothermal composite by introducing a series of regularly arranged circular holes.

[0033] The surface area can be controlled. The regular arrangement of circular holes effectively controls the surface area of ​​the electrothermal composite. The size of the surface area directly affects the heating temperature of the electrothermal composite. By adjusting the number, size and arrangement of the holes, the surface area of ​​the electrothermal composite can be precisely controlled, and thus its heating temperature can be controlled.

[0034] Furthermore, the heat is evenly spread, and the regular arrangement of circular holes allows the heat to be spread more evenly to the surface of the electrothermal composite. This is because the presence of the holes breaks the continuity of the electrothermal material layer, forming a "network" for heat propagation, making it easier for the heat to be evenly distributed throughout the electrothermal composite. The holes, as channels for heat, not only improve the heat dissipation performance of the electrothermal composite, but also help reduce the temperature rise of the electrothermal composite in a high-temperature working environment, thereby improving the thermal stability of the electrothermal composite.

[0035] Improve the accuracy and stability of temperature control. By precisely controlling the surface area and heat distribution of the electrothermal composite, the present invention significantly improves the accuracy and stability of temperature control. This helps to avoid the problem of excessively high or low local temperatures on the surface of the electrothermal composite, and ensures that the electrothermal composite can maintain stable performance under different working environments.

[0036] Increased flexibility and plasticity, the regular arrangement of circular holes makes the electric heating film more flexible and plastic. This makes the electric heating composite more suitable for application scenarios of different shapes and sizes, such as curved surface heating, special-shaped heating, etc.

[0037] By improving the heat dissipation effect and the accuracy of temperature control, the present invention reduces the safety risk caused by overheating of the electric heating composite and improves the safety of the use of the electric heating composite. Due to the improved heat dissipation effect and the improved stability of temperature control, the present invention helps to reduce the aging speed of the electric heating composite, thereby extending its service life.

[0038] As an optional solution, the size, number and arrangement of the holes in the electrothermal composite of the present invention can be adjusted according to actual needs to meet the requirements of temperature control and electrothermal performance in different application scenarios. By introducing a series of regularly arranged circular holes, the performance of the electrothermal composite is optimized and improved.

[0039] Preferably, the materials of the base insulating layer 4 and the encapsulating insulating layer 1 are one or more of epoxy resin, polyester, polyurethane, silicone resin, polyimide alkyd resin, polyimide, polybutadiene, polystyrene, polypropylene, polycarbonate, polytetrafluoroethylene and silicone rubber.

[0040] Preferably, the electrothermal material is at least one of a carbon material and a conductive metal material.

[0041] Preferably, the high molecular polymer is at least one of thermoplastic polyurethane, polyvinylidene fluoride, epoxy resin, polyacrylonitrile and ABS resin.

[0042] Preferably, the solvent is one or more of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like.

[0043] Preferably, the circular hole has a diameter of 5-20 mm, for example, 5-15 mm, 10-20 mm, 10-15 mm, 5 mm, 7 mm, 8 mm, 10 mm, 12 mm, 13 mm, 15 mm, 17 mm, 18 mm, 19 mm, 20 mm, etc.

[0044] The spacing between each two adjacent holes is 5-20 mm. For example, it can be: 5-15 mm, 10-20 mm, 10-15 mm, 5 mm, 6 mm, 8 mm, 10 mm, 11 mm, 14 mm, 15 mm, 16 mm, 18 mm, 18.5 mm, 20 mm, etc.

[0045] Preferably, the distribution of the regular circular holes includes a square arrangement, a spiral arrangement or a random arrangement.

[0046] The second object of the present invention is to provide a method for preparing the above-mentioned temperature-controllable electrothermal composite, comprising the following steps: (1) dissolving a high molecular weight polymer in an organic solvent and preparing a high molecular weight polymer glue by mechanical stirring under heating conditions; The heating temperature range is 60-150° C. For example, it can be 60-120° C., 100-150° C., 80-100° C., 60° C., 80° C., 90° C., 100° C., 120° C., 130° C., 140° C., 150° C., and the like.

[0047] (2) adding an appropriate amount of electric heating material to the high molecular polymer glue prepared in step (1), and mixing the electric heating material and the high molecular polymer glue thoroughly and evenly by mechanical stirring to form an electric heating composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the base insulating layer 4 by a slurry scraping method, and the electrothermal composite is formed after high-temperature curing; The curing temperature range is 60-150° C. For example, it can be 60-120° C., 100-150° C., 80-100° C., 60° C., 70° C., 80° C., 100° C., 120° C., 130° C., 145° C., 150° C., and the like.

[0048] (4) Punching corresponding circular holes on the surface of the electrothermal composite with a punch of corresponding size; (5) Placing a copper electrode on the surface of the electrothermal composite prepared in step (3), and packaging it using a plastic packaging machine to obtain an electrothermal composite with a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer 1.

[0049] The preparation method of the temperature-controllable electric heating composite of the present invention is based on the following principle: the dissolution of a polymer in an organic solvent is a physical process, and the dissolution can be accelerated by heating and mechanical stirring to form a uniform polymer glue. This step provides a basis for the subsequent mixing of electric heating materials. The electric heating material (such as electric heating wire, electric heating film fragments, electric heating powder, etc.) is added to the polymer glue and uniformly dispersed by mechanical stirring. In this way, the electric heating material can form a continuous conductive network in the polymer, providing a basis for the heating performance of the electric heating composite. The electric heating composite slurry is uniformly coated on the surface of the substrate insulation layer by a slurry scraping method to ensure the uniform distribution of the electric heating material on the substrate insulation layer. The high-temperature curing process causes the solvent in the polymer glue to volatilize, and the polymer chain segments are rearranged and cross-linked and cured to form a stable electric heating composite structure. At the same time, the electric heating material is also firmly fixed on the substrate insulation layer. Circular holes are punched on the surface of the electric heating composite, which may be for installing temperature sensors, connecting wires or realizing other functions. The copper electrode is placed on the surface of the electrothermal composite and encapsulated by a plastic encapsulator to form a "sandwich" structure. This step ensures good contact between the electrothermal composite and the electrode and provides electrical connection for the use of the electrothermal composite.

[0050] The preparation process of the present invention mainly includes the steps of dissolving, mixing, coating, curing and packaging, and the process is relatively simple and easy to operate and control. The raw materials used (polymer, electric heating material, organic solvent, etc.) are relatively cheap, and no complicated equipment and process are required in the preparation process, which reduces the production cost. By adjusting the concentration of the polymer glue, the type and content of the electric heating material, the coating thickness and other parameters, the heating performance and temperature control range of the electric heating composite can be accurately controlled. The high temperature curing process enables the electric heating composite to form a stable structure with good mechanical strength and durability. At the same time, the encapsulation insulation layer and the substrate insulation layer provide additional protection to ensure the electrical safety and reliability of the electric heating composite.

[0051] The technical solution of the present invention is further described in detail below through specific embodiments in conjunction with the accompanying drawings.

[0052] Embodiment 1: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 60°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at a high temperature of 110° C. for 24 h to form an electrothermal composite; (4) Use a 5 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with a spacing of 10 mm between each adjacent hole; (5) Placing a copper electrode on the surface of the electrothermal composite prepared in step (3), and packaging it using a plastic packaging machine to obtain an electrothermal composite with a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0053] The resistance and electrothermal properties of the prepared electrothermal composite were tested, and the resistance was 37 Ω·mm. The electrical properties were tested as follows: Figure 2 As shown in the figure, the electric heating film reaches a constant temperature within 100 s under a voltage of 12 V, with a maximum temperature of 104°C, and can work stably at the highest temperature.

[0054] Embodiment 2: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 60°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at a high temperature of 110° C. for 24 h to form an electrothermal composite; (4) Use a 10 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with the spacing between each two adjacent holes being 10 mm; (5) Placing a copper electrode on the surface of the composite heating layer prepared in step (3), and packaging it using a plastic packaging machine to obtain an electric heating composite of a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0055] The resistance and electrothermal performance tests of the prepared electrothermal composite showed that the resistance was 53 Ω·mm. Under a voltage of 12V, the electrothermal film reached a constant temperature within 100 s, with a maximum temperature of 80℃, and could work stably at the highest temperature.

[0056] Embodiment 3: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 60°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at a high temperature of 110° C. for 24 h to form an electrothermal composite; (4) Use a 15 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with a spacing of 10 mm between each adjacent hole; (5) Placing a copper electrode on the surface of the electrothermal composite prepared in step (3), and packaging it using a plastic packaging machine to obtain an electrothermal composite with a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0057] The resistance and electrothermal performance tests of the prepared electrothermal composite showed that the resistance was 69 Ω·mm. Under a voltage of 12V, the electrothermal film reached a constant temperature within 100 s, with a maximum temperature of 62°C, and could work stably at the highest temperature.

[0058] Embodiment 4: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 60°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at a high temperature of 110° C. for 24 h to form an electrothermal composite; (4) Use a 20 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with a spacing of 10 mm between each adjacent hole; (5) Placing a copper electrode on the surface of the composite heating layer prepared in step (3), and packaging it using a plastic packaging machine to obtain an electric heating composite of a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0059] The resistance and electrothermal performance tests of the prepared electrothermal composite showed that the resistance was 97 Ω·mm. Under a voltage of 12V, the electrothermal film reached a constant temperature within 100 s, with a maximum temperature of 50°C, and could work stably at the highest temperature.

[0060] Embodiment 5: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 65°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at a high temperature of 125° C. for 22 h to form an electrothermal composite; (4) Use a 16 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with the spacing between each two adjacent holes being 12 mm; (5) Placing a copper electrode on the surface of the composite heating layer prepared in step (3), and packaging it using a plastic packaging machine to obtain an electric heating composite of a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0061] The resistance and electrothermal performance tests of the prepared electrothermal composite showed that the resistance was 96 Ω·mm. Under a voltage of 12V, the electrothermal film reached a constant temperature within 100 s, with a maximum temperature of 51°C, and could work stably at the highest temperature.

[0062] Embodiment 6: A temperature-controllable electric heating composite, the specific material composition and steps in implementation are: (1) Dissolving an appropriate amount of polyimide powder in N-N-dimethylacetamide solution, and preparing PI-DMAc solution by mechanical stirring at 85°C; (2) adding graphite and glass fiber in appropriate weights to the PI-DMAc solution prepared in step (1), and placing the solution on a constant temperature magnetic stirrer for stirring and dispersing at a certain speed to form an electrothermal composite slurry; (3) The electrothermal composite slurry prepared in step (2) is uniformly coated on the surface of the polyimide film by a slurry coating method, and is cured at 90° C. for 22 h to form an electrothermal composite; (4) Use a 15 mm punch to punch out corresponding circular holes on the surface of the electrothermal composite, with the spacing between each two adjacent holes being 13 mm; (5) Placing a copper electrode on the surface of the composite heating layer prepared in step (3), and packaging it using a plastic packaging machine to obtain an electric heating composite of a "sandwich" structure of a base insulating layer - a composite heating layer - a packaging insulating layer.

[0063] The resistance and electrothermal performance tests of the prepared electrothermal composite showed that the resistance was 95 Ω·mm. Under a voltage of 12V, the electrothermal film reached a constant temperature within 100 s, with a maximum temperature of 49°C, and could work stably at the highest temperature.

[0064] It can be seen that the composite heating layer of the present invention has a series of regularly arranged circular holes, which makes the temperature distribution more uniform and helps to improve the accuracy of temperature control. Overall, the supporting performance, fatigue resistance and bending resistance are improved, and the risk of electrical breakdown is reduced. Therefore, it has broad market application prospects.

[0065] The above-described embodiment is only a preferred solution of the present invention and does not limit the present invention in any form. There are other variations and modifications without exceeding the technical solution described in the claims.

Claims

1. A temperature-controllable electrothermal composite, characterized in that: It includes a composite heating layer, an encapsulation insulating layer, and a copper foil electrode sandwiched between the composite heating layer and the encapsulation insulating layer. A base insulating layer is provided below the composite heating layer, and a series of regularly arranged circular holes are provided on the composite heating layer; the encapsulation insulating layer encapsulates the copper foil electrode and the composite heating layer on the base insulating layer.

2. The temperature-controllable electrothermal composite according to claim 1, characterized in that: The materials of the base insulating layer and the encapsulating insulating layer are one or more of epoxy resin, polyester, polyurethane, silicone resin, polyimide alkyd resin, polyimide, polybutadiene, polystyrene, polypropylene, polycarbonate, polytetrafluoroethylene and silicone rubber.

3. The temperature-controllable electrothermal composite according to claim 1, characterized in that: The composite heating layer is composed of high molecular polymer, electric heating material and organic solvent.

4. The temperature-controllable electrothermal composite according to claim 3, characterized in that: The electric heating material is at least one of a carbon material and a conductive metal material.

5. The temperature-controllable electrothermal composite according to claim 3, characterized in that: The high molecular polymer is at least one of thermoplastic polyurethane, polyvinylidene fluoride, epoxy resin, polyacrylonitrile and ABS resin; the solvent is one or more of dimethylformamide, dimethylacetamide, N-methyl-2-pyrrolidone, dimethyl sulfoxide and the like.

6. The temperature-controllable electrothermal composite according to claim 3, characterized in that: The circular holes have a diameter of 5-20 mm, and the distance between two adjacent holes is 5-20 mm.

7. The temperature-controllable electrothermal composite according to claim 3, characterized in that: The distribution form of the regular circular holes includes square arrangement, spiral arrangement or random arrangement.

8. A method for preparing a temperature-controllable electrothermal composite according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: S1, dissolving a high molecular polymer in an organic solvent, and stirring under heating conditions to prepare a high molecular polymer glue; S2, adding the electric heating material to the high molecular polymer glue, and stirring to fully mix the electric heating material with the high molecular polymer glue to form an electric heating composite slurry; S3, using a slurry scraping method to evenly apply the electric heating composite slurry on the surface of the substrate insulation layer, and forming a composite heating layer after curing; S4. Punch out corresponding circular holes on the surface of the composite heating layer with a punch of corresponding size; S5. Placing a copper electrode on the surface of the prepared composite heating layer, and encapsulating the insulating layer to obtain an electric heating composite.

9. The method for preparing the temperature-controllable electrothermal composite according to claim 8, characterized in that: The heating temperature range in S1 is 60~150℃.

10. The method for preparing the temperature-controllable electrothermal composite according to claim 8, characterized in that: The curing temperature range in S3 is 60~150℃.

Images