Wear-resistant electric heating material as well as preparation method and application thereof

Abstract

The invention discloses a wear-resistant electric heating material and a preparation method and application thereof, and belongs to the technical field of new materials. S1, a monomer A is added into water and uniformly dispersed; s2, adding a carbon material into the solution in the S1, and uniformly dispersing; s3, sequentially adding a catalyst and acid when the mixture is stirred until no particulate matter exists, and stirring in a dark place to obtain a wear-resistant electric heating material precursor; s4, carrying out heat treatment on the wear-resistant electric heating material precursor to obtain the wear-resistant electric heating material.The wear-resistant electric heating material has the beneficial effects that the wear-resistant electric heating material monomer A is introduced, a mutually-staggered space structure is creatively formed through four reaction sites under the action of a specific catalyst and an acid reagent, the unexpected hardness of polymer molecules is obtained, and the wear-resistant electric heating material has the advantages that the wear-resistant electric heating material is obtained; the wear resistance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials, and in particular relates to a wear-resistant electric heating material and a preparation method and application thereof. Background Art

[0002] Compared with traditional heating elements such as resistance wire, ceramic PTC, electric heating tube and quartz tube, carbon-containing electric heating materials have gradually developed into the core material of new electric heating elements due to their advantages such as uniform heating and long life, and have expanded to a wider range of application fields; the current mainstream carbon-containing electric heating materials are graphene-based electric heating materials, which perform excellently in low-temperature (≤80°C) static scenarios, such as the technologies described in patents CN111683420 A and CN106229081 A. In such scenarios, graphene electric heating materials can be encapsulated in a double-layer film material through a hot melt or melting process through flexible film materials such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), polyimide (PI), thermoplastic polyurethane (TPU), etc. to form a stable structure. At the same time, the static environment avoids mechanical damage to the electric heating material by external forces, thereby significantly improving its service life.

[0003] However, the application of graphene heating materials has obvious limitations: first, when the operating temperature exceeds 80°C, low-melting-point film materials (such as PVC) will melt and become unusable; if the temperature rises above 150°C, conventional film materials cannot be used; second, in scenarios that need to withstand long-term mechanical vibrations, such as cables, transportation vehicles, industrial equipment, washing machines and other home appliances, traditional graphene heating elements are difficult to achieve stable high-temperature operation and cannot resist structural damage in dynamic environments.

[0004] Taking into account the heating needs in dynamic environments and combining the performance advantages of carbon-containing electric heating materials, we have independently developed a wear-resistant electric heating material that can be used in cross-linked polyethylene insulated power cables and cable accessories, transportation vehicles, industrial equipment, washing machines, etc., especially to improve the wear resistance and heating and deicing performance of power cables and cable accessories. Compared with the existing technology, the wear-resistant electric heating material provided by the present invention has excellent wear resistance. According to the ISO 1518-2 standard test method, under 1kg load conditions, after 500 cycles of friction at a rate of 50 cycles / minute using CS-10 friction medium, the material surface remains intact and no wear-through occurs. This feature ensures that the present invention can maintain long-term stable working performance under frequent mechanical vibration conditions. Summary of the Invention

[0005] In order to solve the above problems and overcome the shortcomings of the existing technology, the present invention provides a wear-resistant electric heating material and its preparation method and application, so as to enable the carbon-containing electric heating material to maintain long-term stable working performance under frequent mechanical vibration conditions.

[0006] The specific technical solution of the present invention to solve the above technical problems is as follows: The present invention provides a wear-resistant electric heating material, which is made of the following components in parts by weight: 100 parts of monomer A; 6-31 parts of carbon material; 0.6-1.3 parts of catalyst; 0.5-6 parts of acid; 26-50 parts of water;

[0007] The monomer A is N,3-diphenylethylene oxide-2-carboxamide, and its structural formula is:

[0008]

[0009] The wear-resistant electric heating material is a network polymer structure, and its structural formula is:

[0010]

[0011] The structure of the wear-resistant electrothermal material of monomer A and polymer of the present invention has the following characteristics:

[0012] (1) There are four reaction sites on monomer A, namely the nitrogen atom, two carbon atoms on the ethylene oxide group, and one oxygen atom. Through these four reaction sites, each monomer A can polymerize with up to four other monomer A molecules, ultimately forming an interlaced spatial structure, ensuring the hardness of the polymer molecules and improving wear resistance;

[0013] (2) The presence of a large number of amide groups in the main structure of the polymer makes the structure of the polymer similar to that of polyimide (PI), thus having good wear resistance;

[0014] (3) The residual hydroxyl end of monomer A during the polymerization process will undergo a dehydration condensation reaction to form an ether bond, further increasing the degree of polymerization of the polymer and improving the wear resistance;

[0015] (4) The phenyl and amide groups in the polymer are conjugated structures, which facilitates the movement of electrons on the polymer and improves the conductivity of the polymer;

[0016] Furthermore, the carbon material includes any one or more of graphene, carbon black, graphite or carbon fiber; in the present invention, the carbon material provides electrical conductivity of the electric heating material on the one hand, and on the other hand, it is dispersed in the pores of the polymer to provide physical support, thereby improving the wear resistance of the electric heating material after drying;

[0017] Furthermore, the catalyst is 9-thioxanthone; 9-thioxanthone, as a photocatalyst, can be excited under light conditions, thereby oxidizing the nitrogen atom in monomer A; the oxidized nitrogen atom then attacks the carbon atom on the ethylene oxide connected to the phenyl group, generating a new chemical bond and a hydroxyl group, ultimately forming a polymer;

[0018] Furthermore, the acid is trifluoromethanesulfonic acid; a trace amount of the acid can provide an acidic environment, on the one hand, promoting the solubility of monomer A in water; on the other hand, the acid can catalyze the dehydration condensation reaction between hydroxyl groups, further increasing the degree of polymerization of the polymer and improving the wear resistance;

[0019] The present invention also provides a method for preparing a wear-resistant electrothermal material, comprising the following steps:

[0020] S1: Add monomer A into water and disperse evenly;

[0021] S2: Add the carbon material to the solution of S1 and disperse it evenly;

[0022] S3: When stirring until no particulate matter is left, a catalyst and an acid are added in sequence, and stirring is carried out in the dark to obtain a wear-resistant electrothermal material precursor;

[0023] S4: heat-treating the wear-resistant electrothermal material precursor to obtain the wear-resistant electrothermal material;

[0024] Furthermore, in step S1, the dispersion is performed by a disperser at a speed of 400-650 rpm;

[0025] Furthermore, in step S2, the dispersion speed is 520-950 rpm;

[0026] Furthermore, in step S3, the stirring speed is 1000-1200 rpm;

[0027] Furthermore, in step S4, the temperature of the heat treatment is 100°C;

[0028] The present invention also provides an application of a wear-resistant electric heating material. The wear-resistant electric heating material precursor is printed on the surface of a substrate by screen printing, baked at 100° C., and cooled to obtain the wear-resistant electric heating material.

[0029] Furthermore, the screen printing used is a 100-mesh screen;

[0030] Furthermore, the baking time is 0.5-1.2 hours;

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) The present invention screen-prints a wear-resistant electrothermal material precursor onto a substrate, which exhibits excellent wear resistance after drying. According to the ISO 1518-2 standard test method, the material surface remains intact and does not show wear-through after 500 cycles of friction using CS-10 friction medium at a rate of 50 cycles / minute under a load of 1 kg.

[0033] (2) The present invention creatively introduces a wear-resistant electric heating material monomer A, wherein the electric heating material monomer A has a total of four reaction sites, namely a nitrogen atom, two carbon atoms on ethylene oxide, and an oxygen atom. Through these four reaction sites, under the action of a specific catalyst and an acidic reagent, an interlaced spatial structure is creatively formed, thereby obtaining an unexpected hardness of the polymer molecule and improving wear resistance;

[0034] (3) The structure of the wear-resistant electric heating material of the present invention is similar to that of polyimide (PI), and therefore has good wear resistance;

[0035] (4) The carboxyl and hydroxyl groups at the ends of the wear-resistant electric heating material of the present invention can undergo intramolecular esterification, eliminating the active groups at the ends of the polymer, further increasing the degree of polymerization of the polymer, and improving the wear resistance of the polymer. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 This is a photo of the wear-resistant electric heating material according to Example 1 of the present invention;

[0037] Figure 2 This is a photo of the wear-resistant electric heating material after testing according to Example 1 of the present invention;

[0038] Figure 3 This is a photo of Comparative Example 1 of the present invention;

[0039] Figure 4 This is a photo after testing comparative example 1 of the present invention;

[0040] Figure 5 This is a photo of Comparative Example 3 of the present invention;

[0041] Figure 6 This is a deep layer photo of Comparative Example 4 of the present invention;

[0042] Figure 7 This is a photo of Comparative Example 5 of the present invention. DETAILED DESCRIPTION

[0043] Specific details in the description of the present invention are only used to fully understand the embodiments of the present invention. However, those skilled in the art should understand that the present invention is not limited to these details. In addition, well-known structures and functions are not described or illustrated in detail to avoid obscuring the key points of the embodiments of the present invention. Those skilled in the art can understand the specific meanings of the above terms in the present invention in specific circumstances.

[0044] Specific implementation of the present invention:

[0045] In order to better understand the present invention, a specific embodiment is used for illustration. It is worth emphasizing that the effects of this embodiment are not substantially different from those of various embodiments within the scope of protection of the present invention, including the respective reagents and the content ratios of the reagents. All of them can achieve the effects described in the present invention and solve the above-mentioned problems. Other combinations are not described here.

[0046] Example 1:

[0047] This embodiment provides a wear-resistant electric heating material and its specific application; the wear-resistant electric heating material of this embodiment includes the following raw materials in weight proportion: 100 parts of monomer A, 6 parts of carbon black, 0.9 parts of 9-thioxanthone, 5.9 parts of trifluoromethanesulfonic acid, and 44 parts of water;

[0048] At room temperature, monomer A was added to water and stirred at a disperser speed of 650 rpm for 20 minutes; carbon black was added to the solution in batches and dispersed at a disperser speed of 840 rpm; after all the carbon black was added, the disperser speed was increased to 1120 rpm and stirred for 20 minutes until the slurry surface was uniform and free of particulate matter; a catalyst and an acid were added and stirred in the dark for 5 minutes; the resulting viscous slurry was the electrothermal material precursor of Example 1;

[0049] The application steps are as follows: before printing, the protective layer material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing (the printing equipment is the TX-5080SF-P screen printing machine of Hangzhou Taoxing Printing Equipment Co., Ltd.), and the screen used is 100 mesh; after printing, it is baked in a forced air oven at 100°C for 0.5 hours, taken out and cooled to room temperature to obtain a wear-resistant electric heating material.

[0050] Example 2:

[0051] This embodiment provides a wear-resistant electric heating material and its specific application; the wear-resistant electric heating material of this embodiment includes the following raw materials in weight proportion: 100 parts of monomer A, 30 parts of carbon black, 1.2 parts of 9-thioxanthone, 5.1 parts of trifluoromethanesulfonic acid, and 27 parts of water;

[0052] At room temperature, monomer A was added to water and stirred at a disperser speed of 560 rpm for 20 minutes; carbon black was added to the solution in batches and dispersed at a disperser speed of 520 rpm; after all the carbon black was added, the disperser speed was increased to 1060 rpm and stirred for 20 minutes until the slurry surface was uniform and free of particulate matter; a catalyst and an acid were added and stirred in the dark for 5 minutes; the resulting viscous slurry was the electrothermal material precursor of Example 2;

[0053] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 1.2 hours, taken out and cooled to room temperature to obtain a wear-resistant electrothermal material.

[0054] Example 3:

[0055] This embodiment provides a wear-resistant electric heating material and its specific application; the wear-resistant electric heating material of this embodiment includes the following raw materials in weight proportion: 100 parts of monomer A, 23 parts of carbon fiber, 0.6 parts of 9-thioxanthone, 4.7 parts of trifluoromethanesulfonic acid, and 50 parts of water;

[0056] At room temperature, monomer A was added to water and stirred for 20 minutes at a dispersing speed of 430 rpm. Carbon fibers were added to the solution in batches and dispersed at a dispersing speed of 950 rpm. After all the carbon fibers were added, the dispersing speed was increased to 1170 rpm and stirred for 20 minutes until the slurry surface was uniform and free of particulate matter. A catalyst and an acid were added and stirred for 5 minutes in the dark. The resulting viscous slurry was the precursor of the electric heating material of Example 3.

[0057] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 0.8 hours, taken out and cooled to room temperature to obtain a wear-resistant electrothermal material.

[0058] Example 4:

[0059] This embodiment provides a wear-resistant electric heating material and its specific application; the wear-resistant electric heating material of this embodiment includes the following raw materials in weight proportion: 100 parts of monomer A, 13 parts of graphite, 1.3 parts of 9-thioxanthone, 2.9 parts of trifluoromethanesulfonic acid, and 35 parts of water;

[0060] At room temperature, monomer A was added to water and stirred for 20 minutes at a dispersing speed of 520 rpm. Graphite was added to the solution in batches and dispersed at a dispersing speed of 660 rpm. After all the graphite was added, the dispersing speed was increased to 1000 rpm and stirred for 20 minutes until the slurry surface was uniform and free of particulate matter. A catalyst and an acid were added and stirred for 5 minutes in the dark. The resulting viscous slurry was the precursor of the electric heating material of Example 4.

[0061] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 1.0 hour, taken out and cooled to room temperature to obtain a wear-resistant electrothermal material.

[0062] Example 5:

[0063] This embodiment provides a wear-resistant electric heating material and its specific application; the wear-resistant electric heating material of this embodiment includes the following raw materials in weight proportion: 100 parts of monomer A, 26 parts of graphene, 1.1 parts of 9-thioxanthone, 0.5 parts of trifluoromethanesulfonic acid, and 29 parts of water;

[0064] At room temperature, monomer A was added to water and stirred for 20 minutes at a dispersing speed of 400 rpm. Graphene was added to the solution in batches and dispersed at a dispersing speed of 710 rpm. After all the graphene was added, the dispersing speed was increased to 1200 rpm and stirred for 20 minutes until the slurry surface was uniform and free of particulate matter. A catalyst and an acid were added and stirred for 5 minutes in the dark. The resulting viscous slurry was the precursor of the electrothermal material of Example 5.

[0065] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a forced air oven at 100° C. for 0.8 hours, taken out and cooled to room temperature to obtain a wear-resistant electrothermal material;

[0066] In the above embodiment, the chemical reaction equation of monomer A after heat treatment is as follows:

[0067]

[0068] The molecular structure of the network polymer finally obtained on the surface of the carbon-containing electric heating material is:

[0069]

[0070] Comparative Example 1:

[0071] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 1, except that: no acid is added;

[0072] The application steps are as follows: before printing, the protective layer material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 0.5 hours, taken out and cooled to room temperature to obtain Comparative Example 1.

[0073] Comparative Example 2:

[0074] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 2, except that: the amount of acid used is 15 parts;

[0075] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 1.2 hours, taken out and cooled to room temperature to obtain Comparative Example 2.

[0076] Comparative Example 3:

[0077] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 2, except that: the acid is replaced by p-toluenesulfonic acid;

[0078] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 1.2 hours, taken out and cooled to room temperature to obtain Comparative Example 3.

[0079] Comparative Example 4:

[0080] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 1, except that: no catalyst is added;

[0081] The application steps are as follows: before printing, the protective layer material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 0.5 hours, taken out and cooled to room temperature to obtain Comparative Example 4.

[0082] Comparative Example 5:

[0083] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 2, except that the catalyst is replaced by the conventional photocatalyst 2-trifluoromethylthioxanthone;

[0084] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a blast oven at 100°C for 1.2 hours, taken out and cooled to room temperature to obtain Comparative Example 5.

[0085] Comparative Example 6:

[0086] The raw material formula and preparation steps of the protective layer of this comparative example are the same as those of Example 2, except that the monomer A is replaced by monomer B;

[0087] The structure of monomer B is:

[0088] The application steps are as follows: before printing, the electrothermal material precursor needs to be stirred evenly in the dark, and then printed on the surface of the substrate by screen printing, using a 100-mesh screen; after printing, it is baked in a forced air oven at 100° C. for 1.2 hours, taken out and cooled to room temperature to obtain Comparative Example 6;

[0089] The feeding amounts of the above examples and comparative examples are shown in Table 1, and the mass of each raw material is 10 grams.

[0090] Table 1 Parameter comparison of each embodiment and comparative example

[0091] monomer Carbon materials catalyst acid Acid addition Example 1 A carbon black 9-Thioxanthone Trifluoromethanesulfonic acid 5.9 Example 2 A carbon black 9-Thioxanthone Trifluoromethanesulfonic acid 5.1 Example 3 A carbon fiber 9-Thioxanthone Trifluoromethanesulfonic acid 4.7 Example 4 A graphite 9-Thioxanthone Trifluoromethanesulfonic acid 2.9 Example 5 A graphene 9-Thioxanthone Trifluoromethanesulfonic acid 0.5 Comparative Example 1 A carbon black 9-Thioxanthone — — Comparative Example 2 A carbon black 9-Thioxanthone Trifluoromethanesulfonic acid 15 Comparative Example 3 A carbon black 9-Thioxanthone p-Toluenesulfonic acid 5.1 Comparative Example 4 A carbon black — Trifluoromethanesulfonic acid 5.9 Comparative Example 5 A carbon black 2-Trifluoromethylthioxanthone Trifluoromethanesulfonic acid 5.1 Comparative Example 6 B carbon black 9-Thioxanthone Trifluoromethanesulfonic acid 5.1

[0092] The present invention conducted appearance and wear resistance tests on the above embodiments and comparative examples. The test contents and methods are shown in Table 2, and the test results are shown in Table 3.

[0093] Table 2 Test content and test methods

[0094]

[0095] Table 3 Comparison of test results of various embodiments and comparative examples

[0096] Appearance wear resistance Example 1 The surface color is uniform and there is no shedding The coating is not worn through Example 2 The surface color is uniform and there is no shedding The coating is not worn through Example 3 The surface color is uniform and there is no shedding The coating is not worn through Example 4 The surface color is uniform and there is no shedding The coating is not worn through Example 5 The surface color is uniform and there is no shedding The coating is not worn through Comparative Example 1 Rough and granular surface The coating was worn through after 40 cycles Comparative Example 2 The surface color is uniform and there is no shedding The coating was worn through after 310 cycles Comparative Example 3 The surface is granular, with low adhesion and falling off. - Comparative Example 4 The surface is uneven, the slurry cannot solidify in the deep layer and remains a viscous liquid - Comparative Example 5 The surface color is uniform, but the adhesion is very poor and the coating is easy to fall off - Comparative Example 6 The surface color is uniform, but the adhesion is poor and the coating is easy to fall off -

[0097] From the above results, it can be seen that Examples 1-5 can meet the requirements of appearance and wear resistance;

[0098] Figure 1 This is a photo of the wear-resistant electric heating material of Example 1. It can be seen that the surface color of the electric heating material of the present invention is uniform and there is no shedding phenomenon; Figure 2 This is a photograph of the wear-resistant electric heating material of Example 1 of the present invention after testing. It can be seen that after 500 cycles of friction using CS-10 friction medium at a rate of 50 cycles / minute under a load of 1 kg according to the ISO 1518-2 standard test method, the material surface of Example 1 remained intact and no wear-through was observed.

[0099] In Comparative Example 1, since no acid was added, the polymerization reaction could hardly proceed, and the carbon material was not evenly dispersed in the polymer, which ultimately resulted in a rough surface of the electrothermal material precursor after drying.

[0100] In Comparative Example 2, due to the addition of excess acid, ethylene oxide preferentially polymerized, and the polyurethane group did not become the main body of the polymer molecule after the polymerization reaction, resulting in reduced wear resistance of the electric heating material of Comparative Example 2;

[0101] Comparative Example 3 used p-toluenesulfonic acid. Although both p-toluenesulfonic acid and trifluoromethanesulfonic acid are strong organic acids, p-toluenesulfonic acid has very low solubility in water and cannot fully mix with monomer A to promote the condensation reaction between the hydroxyl groups, ultimately resulting in a reduced degree of polymerization of the polymer and easy shedding. In addition, p-toluenesulfonic acid has both hydrophobic phenyl groups and hydrophilic sulfonic acid groups, and it easily forms micelles in water to encapsulate part of the carbon material, resulting in a grainy surface after printing.

[0102] In Comparative Example 4, no photocatalyst was added, and the polymerization reaction was almost impossible to proceed. Only the surface slurry partially reacted under the heating conditions, and the deep slurry could not be solidified.

[0103] Comparative Example 5 uses 2-trifluoromethylthioxanthone instead of 9-thioxanthone as the photocatalyst. Although the main structure of both is thioxanthone, the trifluoromethyl group as an electron-withdrawing group causes the absorption spectrum of 2-trifluoromethylthioxanthone to blue-shift. The light source used in the present invention is indoor natural light or incandescent light, in which the blue light intensity is weak and insufficient to excite 2-trifluoromethylthioxanthone, and thus cannot effectively catalyze the polymerization reaction. Ultimately, the polymerization reaction is almost impossible to proceed, and the coating easily falls off.

[0104] Comparative Example 6 uses monomer B instead of monomer A. Although both monomer B and monomer A have ethylene oxide groups as reaction sites for polymerization, the two phenyl groups attached to the nitrogen atom in monomer B increase the steric hindrance of the nitrogen atom. On the one hand, this makes the nitrogen atom less susceptible to proton attack, promoting the dissolution of monomer B in water. On the other hand, the increased steric hindrance of the nitrogen atom makes it less likely for the epoxy groups on other monomer molecules to undergo nucleophilic attack, reducing the degree of polymerization of the polymer. These two factors together lead to poor coating adhesion and easy detachment.

[0105] The present invention further studies the preparation method of monomer A. The above research shows that monomer A has substantial characteristics compared with other monomers in preparing high molecular ester polymers as wear-resistant electric heating materials, especially annular high molecular ester polymers as wear-resistant electric heating materials.

[0106] The preparation method of monomer A has not yet been reported, and similar working principles have not been retrieved. Therefore, the application further explains the preparation scheme of monomer A:

[0107] In the following examples and comparative examples, each weight portion of various raw materials is 10 g;

[0108] In the following examples and comparative examples, the synthesis method and NMR data of monomer A are as follows:

[0109]

[0110] Example 6:

[0111] S1: Synthesis of cinnamoyl chloride (2):

[0112] Cinnamic acid 1 (7 mmol) was mixed with tetrahydrofuran (25 mL), and the mixture was stirred in an ice bath for 10 minutes; oxalyl chloride (7 mmol) was slowly added to the mixture, and the mixture was stirred in an ice bath for 4 hours to obtain a solution of compound 2 for use;

[0113] S2: Synthesis of N-phenylcinnamamide (3):

[0114] A solution of aniline (7.5 mmol) in tetrahydrofuran (10 mL) was slowly added dropwise to the solution of compound 2. After the addition was complete, the mixture was heated and stirred at 50° C. for 30 minutes. After the reaction was complete, the mixture was extracted three times with ethyl acetate and water. The organic phases were combined and dried to obtain a crude product 3.

[0115] S3: Synthesis of N,3-diphenyloxirane-2-carboxamide (A):

[0116] The crude product 3 (6 mmol), m-chloroperbenzoic acid (6.5 mmol) and diethyl ether (50 mL) were mixed; the mixture was stirred at room temperature for 24 hours; after the reaction, it was extracted three times with ethyl acetate; and the crude product was purified by silica gel column chromatography (PE / EtOAc=2:1) ​​to obtain monomer A.

[0117] Example 7:

[0118] S1: Synthesis of cinnamoyl chloride (2):

[0119] Cinnamic acid 1 (85 mmol) was mixed with tetrahydrofuran (200 mL), and the mixture was stirred in an ice bath for 10 minutes; oxalyl chloride (45 mmol) was slowly added to the mixture, and the mixture was stirred in an ice bath for 7 hours to obtain a solution of compound 2 for use;

[0120] S2: Synthesis of N-phenylcinnamamide (3):

[0121] A solution of aniline (40 mmol) in tetrahydrofuran (100 mL) was slowly added dropwise to the solution of compound 2. After the addition was complete, the mixture was heated and stirred at 50° C. for 80 minutes. After the reaction was complete, the mixture was extracted three times with ethyl acetate and water. The organic phases were combined and dried to obtain a crude product 3.

[0122] S3: Synthesis of N,3-diphenyloxirane-2-carboxamide (A):

[0123] The crude product 3 (37 mmol), m-chloroperbenzoic acid (39 mmol) and diethyl ether (250 mL) were mixed; the mixture was stirred at room temperature for 24 hours; after the reaction, it was extracted three times with ethyl acetate; and the crude product was purified by silica gel column chromatography (PE / EtOAc=2:1) ​​to obtain monomer A.

[0124] Example 8:

[0125] S1: Synthesis of cinnamoyl chloride (2):

[0126] Cinnamic acid 1 (50 mmol) was mixed with tetrahydrofuran (100 mL), and the mixture was stirred in an ice bath for 10 minutes; oxalyl chloride (30 mmol) was slowly added to the mixture, and the mixture was stirred in an ice bath for 5 hours to obtain a solution of compound 2 for use;

[0127] S2: Synthesis of N-phenylcinnamamide (3):

[0128] A solution of aniline (52 mmol) in tetrahydrofuran (100 mL) was slowly added dropwise to the solution of compound 2. After the addition was complete, the mixture was heated and stirred at 50°C for 45 minutes. After the reaction was complete, the mixture was extracted three times with ethyl acetate and water. The organic phases were combined and dried to obtain a crude product 3.

[0129] S3: Synthesis of N,3-diphenyloxirane-2-carboxamide (A):

[0130] The crude product 3 (50 mmol), m-chloroperbenzoic acid (54 mmol) and diethyl ether (200 mL) were mixed; the mixture was stirred at room temperature for 24 hours; after the reaction, it was extracted three times with ethyl acetate; and the crude product was purified by silica gel column chromatography (PE / EtOAc=2:1) ​​to obtain monomer A;

[0131] 1 H NMR(CDCl3,500MHz)δ3.81(d,J=5.0Hz,1H),4.29(d,J=4.0Hz,1H),6.90-6.97( m,1H),7.06-7.12(m,4H),7.14-7.22(m,3H),7.29-7.32(m,2H),7.58(brs,1H); 13 C NMR (CDCl3, 126MHz) δ56.5,58.5,120.1,124.7,126.3,128.4,128.5,128.7,132.6,135.9,164.4.

[0132] Table 4 Yield and purity of monomer A in each embodiment and its application parameters

[0133] Yield purity Appearance wear resistance Example 6 88％ 99.7％ White solid The coating is not worn through Example 7 80％ 99.6％ White solid The coating is not worn through Example 8 83％ 99.7％ White solid The coating is not worn through

[0134] As can be seen from Table 4, the monomer A prepared in Examples 6-8 has a good yield of more than 83% and a purity of more than 99%. The prepared monomer A is obtained according to the method disclosed in the present invention to obtain a wear-resistant electric heating material, all of which have superior appearance and wear resistance, and there is no significant difference between the examples.

[0135] In summary,

[0136] (1) The present invention screen-prints a wear-resistant electrothermal material precursor onto a substrate, which exhibits excellent wear resistance after drying. According to the ISO 1518-2 standard test method, the material surface remains intact and does not show wear-through after 500 cycles of friction using CS-10 friction medium at a rate of 50 cycles / minute under a load of 1 kg.

[0137] (2) The present invention creatively introduces a wear-resistant electric heating material monomer A, wherein the electric heating material monomer A has a total of four reaction sites, namely a nitrogen atom, two carbon atoms on the ethylene oxide group, and an oxygen atom. Through these four reaction sites, under the action of a specific catalyst and an acidic reagent, each monomer A can be creatively polymerized with up to four other monomer A molecules, ultimately forming an interlaced spatial structure, obtaining an unexpected hardness of the polymer molecules and improving wear resistance;

[0138] (3) The structure of the wear-resistant electric heating material of the present invention is similar to that of polyimide (PI), and therefore has good wear resistance;

[0139] (4) The carboxyl and hydroxyl groups at the ends of the wear-resistant electric heating material of the present invention can undergo intramolecular esterification, eliminating the active groups at the ends of the polymer, further increasing the degree of polymerization of the polymer, and improving the wear resistance of the polymer.

[0140] To enable carbon-containing electric heating materials to operate stably under frequent mechanical vibration conditions, the present invention has developed a wear-resistant electric heating material. Compared with existing technologies, the wear-resistant electric heating material provided by the present invention has excellent wear resistance. According to the ISO 1518-2 standard test method, under a load of 1 kg, after 500 cycles of friction using CS-10 friction medium at a rate of 50 cycles / minute, the material surface remained intact and showed no wear-through. This property ensures that the present invention can maintain long-term stable performance under frequent mechanical vibration conditions.

[0141] The above description of the embodiments is to facilitate ordinary technicians in this technical field to understand and use the invention; those familiar with the technology in this field can obviously easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without having to engage in creative work; therefore, the present invention is not limited to the above-mentioned embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A wear-resistant electric heating material, characterized in that The invention is prepared by using the following components in parts by weight: 100 parts of monomer A; 6-31 parts of carbon material; 0.6-1.3 parts of catalyst; 0.5-6 parts of acid; 26-50 parts of water; The monomer A is N,3-diphenylethylene oxide-2-carboxamide, and its structural formula is:

2. The wear-resistant electric heating material according to claim 1, characterized in that The carbon material includes any one or more of graphene, carbon black, graphite or carbon fiber.

3. The wear-resistant electric heating material according to claim 1, characterized in that The catalyst is 9-thioxanthone.

4. The wear-resistant electric heating material according to claim 1, characterized in that The acid is trifluoromethanesulfonic acid.

5. A method for preparing a wear-resistant electric heating material, using the components of the wear-resistant electric heating material according to any one of claims 1 to 4, characterized in that The following steps are involved: S1: Add monomer A into water and disperse evenly; S2: Add the carbon material to the solution of S1 and disperse it evenly; S3: When stirring until no particulate matter is left, a catalyst and an acid are added in sequence, and stirring is carried out in the dark to obtain a wear-resistant electrothermal material precursor; S4: heat-treating the wear-resistant electrothermal material precursor to obtain the wear-resistant electrothermal material.

6. The method for preparing the wear-resistant electric heating material according to claim 5, characterized in that The temperature of the heat treatment is 100°C.

7. The method for preparing the wear-resistant electric heating material according to claim 6, characterized in that The wear-resistant electric heating material is a network polymer structure, and its structural formula is:

8. A method for applying a wear-resistant electric heating material, comprising: printing the wear-resistant electric heating material precursor obtained by the preparation method of the wear-resistant electric heating material according to claim 5 on the surface of a substrate by screen printing, baking the precursor at 100°C to form the precursor, and cooling the precursor to obtain the wear-resistant electric heating material.

9. The application method of the wear-resistant electric heating material according to claim 8, characterized in that The screen printing used was a 100-mesh screen.

10. The application method of the wear-resistant electric heating material according to claim 9, characterized in that The baking time is 0.5-1.2 hours.

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