Preparation method and application of low-resistivity electrothermal material
By preparing low resistivity electrothermal materials, the problem of high-temperature heating under low voltage was solved by utilizing the esterification reaction of monomer A and screen printing, thus achieving the satisfaction of safe voltage and the uniformity and stability of the material.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- JIANGSU FUNUAN TECH CO LTD
- Filing Date
- 2024-11-01
- Publication Date
- 2026-05-15
AI Technical Summary
Existing low-resistivity electrothermal materials cannot achieve high-temperature heating at low voltages, and traditional methods suffer from problems such as high cost or large size, failing to meet safety voltage requirements.
Low resistivity electrothermal materials are prepared by screen printing using a mixture of monomer A, carbon materials, acid, and water. The esterification reaction of monomer A forms a spatial network structure, which increases adhesion and ensures uniform dispersion of carbon materials, thereby reducing resistivity.
It achieves high-temperature heating under low voltage, meets safety voltage requirements, is suitable for home environments, and exhibits good material uniformity and stability.
Smart Images
Figure CN122037145A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of new materials technology, specifically to a method for preparing and applying a low resistivity electrothermal material. Background Technology
[0002] With increasing emphasis on electrical safety, the development of low-resistivity heating materials has become a key technology for improving the performance and enhancing the safety of electrical equipment. This technology's rise is attributed to the continuous maturation of low-voltage heating technology and the growing consumer demand for electrical safety. Traditional resistance wire heating elements require reducing the resistance of the wire to achieve high-temperature heating under low voltage. There are two main methods: one is to use a metal with lower resistivity as the heating element; the other is to increase the diameter of the resistance wire or shorten its length. However, the former requires relatively expensive metals such as silver and gold, while the latter may result in a larger, heavier heating element, unsuitable for home environments.
[0003] Graphene, as an emerging electrothermal material, has demonstrated some innovative achievements in the field of low-voltage heating. For example, patents CN 114836078 A, CN 106450376 A, CN 113096885 A, and CN 114559710 A all disclose methods for preparing low-resistance electrothermal films or materials. Among them, the graphene conductive paste invented in patent CN 114836078 A has a resistivity of 1.5-2.6 × 10⁻⁶. -2 The resistivity of the conductive carbon film invented in patent CN 106450376 A is 2-10 Ω·m; the resistivity of the conductive film invented in patent CN 113096885 A is 200-700 Ω·m; the resistivity of the low-pressure heating composite material invented in patent CN 114559710 A is 800-2000 Ω·m. However, from the perspective of product application, only resistivity less than 10 Ω·m is suitable. -5 Only materials with a resistivity of Ω·m can truly achieve high heat generation over a large area under low voltage conditions. The resistivity of the aforementioned inventions is relatively high, therefore they cannot be successfully applied in the field of low-voltage heating.
[0004] To expand the application areas of low-voltage heating technology, we have developed a low-resistivity electrothermal material with a minimum resistivity as low as 2.1 × 10⁻⁶. -6The resistivity (Ω·m) meets the requirements for low-resistivity materials. Our invented electrothermal material, when fabricated into an electric heating element, can generate high-temperature heating under low-voltage power supply conditions. This patent also discloses its preparation method and application. The above components are mixed and then screen-printed onto a mica substrate. After heating and curing, a low-resistivity electrothermal material is obtained. Using this electrothermal material to make an electric heating element enables high-temperature heating under low voltage, meeting users' requirements for safe voltage. Summary of the Invention
[0005] The purpose of this invention is to provide a low-resistivity electrothermal material, its preparation method, and its application. The above-mentioned components are mixed and then screen-printed onto a mica substrate. After heating and curing, a low-resistivity electrothermal material is obtained. Using this electrothermal material to make an electrothermal element enables high-temperature heating at low voltage, meeting users' requirements for safe voltage.
[0006] To achieve the objectives of this invention, the technical solution adopted is as follows:
[0007] A low resistivity electrothermal material, characterized in that the raw materials comprising the following components in the indicated weight proportions:
[0008] 100 units of monomer A;
[0009] 34-80 parts carbon material;
[0010] 0.7-5.1 parts acid;
[0011] 65-95 parts water.
[0012] The monomer A is 4-(3,5-dihydroxyphenyl)ethynyl)benzoic acid, and its structural formula is: This structure has the following characteristics:
[0013] 1. Each monomer A molecule has two phenolic hydroxyl groups and one carboxyl group. In an acidic environment, the phenolic hydroxyl and carboxyl groups undergo an esterification reaction upon heating and baking, ultimately forming a three-dimensional network structure, as shown in the figure. Figure 2 As shown.
[0014] 2. The polymer molecules contain a large number of terminal hydroxyl and ester groups. The oxygen and hydrogen atoms on these two groups can form hydrogen bonds with silicon, sodium, potassium and other atoms on the surface of the mica board, thereby increasing adhesion.
[0015] 3. The large number of planar phenyl structures present in the polymer structure can further increase the adhesion between the polymer and mica with its sheet-like structure.
[0016] 4. The pores of polymer molecules contain polar hydroxyl groups and non-polar aromatic structures. These factors work together to promote the uniform dispersion of carbon molecules in their pores, so no additional dispersant is needed.
[0017] 5. The hydroxyl and carboxyl groups on the monomer molecules are hydrophilic groups, so the monomer molecules have good solubility in water, which makes it easy to adjust the viscosity of carbon materials and facilitates screen printing.
[0018] 6. The numerous pores in the polymer structure can accommodate a large amount of carbon material, reducing the resistance after drying. Therefore, the resistance of this low-resistivity heating material can be adjusted within a wide range to meet the heating requirements of various electric heating products.
[0019] The carbon material is one of carbon nanotubes, conductive carbon black, graphene, or graphite. In this invention, the carbon material provides good electrical conductivity for the electrothermal material.
[0020] The acid is one of sulfuric acid, sulfurous acid, or sodium bisulfate. The acid provides an acidic environment that promotes the protonation of hydroxyl and carboxyl groups, increasing the solubility of monomer A in water. Furthermore, the acidic environment weakens the carbon-oxygen double bond on the carboxyl group, promoting esterification.
[0021] The water used is tap water. Water can reduce the viscosity of the electrothermal material precursor, making it easier for screen printing.
[0022] A method for preparing a low resistivity electrothermal material, characterized by comprising the following steps:
[0023] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 450-750 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 700-1000 rpm. After all the material has been added, the disperser speed is increased to 1100-1350 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is a precursor for low resistivity electrothermal materials.
[0024] An application of a low resistivity electrothermal material, specifically:
[0025] First, the low resistivity electrothermal material precursor is stirred evenly, and then printed onto a mica substrate by screen printing. After printing, it is baked in a forced-air oven at 70°C for 0.5-1 hour. The substrate is then removed and cooled to room temperature. Silver paste is then printed onto both ends of the electrothermal material by screen printing. Next, it is baked in a forced-air oven at 40°C for 0.5 hours. The substrate is then removed and cooled to room temperature to obtain a low resistivity electrothermal material.
[0026] In a preferred embodiment of the present invention, the diameter of the carbon nanotubes is less than 15 nm.
[0027] In a preferred embodiment of the present invention, the mass fraction of sulfuric acid in the sulfurous acid is ≤0.5%.
[0028] In a preferred embodiment of the present invention, screen printing requires two passes.
[0029] In a preferred embodiment of the present invention, the oven needs to be preheated to 70°C before baking.
[0030] The beneficial effects of this invention are as follows:
[0031] The above components are mixed and then screen-printed onto a mica substrate. After heating and curing, a low-resistivity electrothermal material is obtained. Using this electrothermal material to make heating elements enables high-temperature heating at low voltage, meeting users' requirements for safe voltage. Attached Figure Description
[0032] Figure 1 Reaction chemical equation
[0033] Figure 2 Schematic diagram of polymer molecular structure
[0034] Figure 3 Example 4: Exterior Photograph
[0035] Figure 4 Comparative Example 1: Exterior Photo
[0036] Figure 5 Example 2 Power Change Curve
[0037] Figure 6 Example 2 Infrared Photograph Detailed Implementation
[0038] The present invention will be described in detail below with reference to specific embodiments, but this is by no means a limitation of the present invention (in the following embodiments, each part by weight of each raw material is 10 grams).
[0039] The following embodiments further illustrate the present invention in detail. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.
[0040] Example 1
[0041] The raw materials of each component according to the following weight ratio are: 100 parts of monomer A, 55 parts of carbon nanotubes, 1.0 part of sulfurous acid, and 80 parts of water.
[0042] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 500 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 810 rpm. After all the material has been added, the disperser speed is increased to 1190 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is the precursor of the low resistivity electrothermal material of Example 1.
[0043] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.5 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Example 1.
[0044] Example 2
[0045] The raw materials of each component according to the following weight ratio are: 100 parts monomer A, 74 parts carbon nanotubes, 3.6 parts sulfurous acid, and 77 parts water.
[0046] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 540 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 860 rpm. After all the material has been added, the disperser speed is increased to 1200 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is the low resistivity electrothermal material precursor of Example 2.
[0047] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.5 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Example 2.
[0048] Example 3
[0049] The raw materials of each component according to the following weight ratio are: 100 parts monomer A, 52 parts graphene, 3.5 parts sulfuric acid, and 87 parts water.
[0050] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 700 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 790 rpm. After all the material has been added, the disperser speed is increased to 1110 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is the low resistivity electrothermal material precursor of Example 3.
[0051] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.8 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Example 3.
[0052] Example 4
[0053] The raw materials of each component according to the following weight ratio are: 100 parts monomer A, 60 parts graphene, 4.1 parts sulfuric acid, and 90 parts water.
[0054] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 470 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 900 rpm. After all the material has been added, the disperser speed is increased to 1310 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is the low resistivity electrothermal material precursor of Example 4.
[0055] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 1 hour. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Example 4.
[0056] Example 5
[0057] The raw materials of each component according to the following weight ratio are: 100 parts monomer A, 80 parts graphene, 3.8 parts sodium bisulfate, and 66 parts water.
[0058] In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 450 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 870 rpm. After all the material has been added, the disperser speed is increased to 1180 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is the low resistivity electrothermal material precursor of Example 5.
[0059] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.7 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Example 5.
[0060] Comparative Example 1
[0061] The raw material formula and preparation steps are the same as in Example 1, except that acid is not added.
[0062] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.5 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Comparative Example 1.
[0063] Comparative Example 2
[0064] The raw material formula and preparation steps are the same as in Example 2. Only the amount of water is reduced by half.
[0065] The application steps are as follows: First, stir the low resistivity electrothermal material precursor evenly, and then print it onto the mica substrate by screen printing. After printing, bake it in a forced-air oven at 70°C for 0.5 hours. Take out the substrate and cool it to room temperature. Then, print silver paste onto both ends of the electrothermal material by screen printing. Next, bake it in a forced-air oven at 40°C for 0.5 hours. Take out the substrate and cool it to room temperature to obtain Comparative Example 2.
[0066] The feed amounts for the above embodiments and comparative examples are shown in Table 1.
[0067] Table 1. Feed amounts for the examples and comparative examples
[0068]
[0069] Note: Each portion of each ingredient weighs 10 grams.
[0070] Examples 1, 2, 3, 4, 5, Comparative Example 1, and Comparative Example 2 were tested according to the standards in Table 2, and the test results are shown in Table 3.
[0071] Table 2 Test Content
[0072]
[0073] Table 3 Test Results
[0074]
[0075] The results above show that Examples 1-5 meet the requirements for appearance, low resistivity, and thermal stability, and the proportion of carbon material has a significant impact on resistivity. In Comparative Example 1, the lack of acid prevented monomer A from polymerizing, resulting in uneven dispersion of the carbon material in the coating. This led to a rough, grainy surface and excessively high resistivity. In Comparative Example 2, the lack of water prevented monomer A from completely dissolving, resulting in an excessively high viscosity of the electrothermal material precursor, making printing impossible.
[0076] The application of this invention is not limited to the examples described above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and equivalent substitutions should fall within the protection scope of the appended claims.
Claims
1. A low resistivity electrothermal material, characterized in that, The components are composed of the following according to their weight proportions: 100 units of monomer A; 34-80 parts carbon material; 0.7-5.1 parts acid; 65-95 parts water.
2. The low resistivity electrothermal material as described in claim 1, characterized in that, The monomer A is 4-(3,5-dihydroxyphenyl)ethynyl)benzoic acid, and its structural formula is:
3. The low resistivity electrothermal material as described in claim 1, characterized in that, The carbon material is one of carbon nanotubes, conductive carbon black, graphene, or graphite.
4. The low resistivity electrothermal material as described in claim 1, characterized in that, The acid mentioned is one of sulfuric acid, sulfurous acid, or sodium bisulfate.
5. The low resistivity electrothermal material as described in claim 1, characterized in that, The water mentioned is tap water.
6. The method for preparing a low resistivity electrothermal material as described in claims 1-5, characterized in that, Includes the following steps: In a room temperature environment, monomer A and acid are added to water and stirred for 40 minutes at a disperser speed of 450-750 rpm. Carbon material is added to the solution in batches and dispersed at a disperser speed of 700-1000 rpm. After all the material has been added, the disperser speed is increased to 1100-1350 rpm and stirred for 0.5 hours until the slurry surface is uniform and free of particulate matter. The resulting viscous slurry is a precursor for low resistivity electrothermal materials.
7. The application of a low resistivity electrothermal material as described in claims 1-5, characterized in that, First, the low resistivity electrothermal material precursor is stirred evenly, and then printed onto a mica substrate by screen printing. After printing, it is baked in a forced-air oven at 70°C for 0.5-1 hour. The substrate is then removed and cooled to room temperature. Silver paste is then printed onto both ends of the electrothermal material by screen printing. Next, it is baked in a forced-air oven at 40°C for 0.5 hours. The substrate is then removed and cooled to room temperature to obtain a low resistivity electrothermal material.