Broadband anti-interference wire harness composite magnetic ring and preparation method thereof

Abstract

The invention discloses a broadband anti-interference wire harness composite magnetic ring and a preparation method thereof, and belongs to the technical field of permanent magnet motors, ferric oxide, manganous-manganic oxide and zinc oxide are used as raw materials, under the action of a multi-element interpenetrating binder, broadband interference signals can be absorbed, and cooperation of anti-interference and magnetic performance is achieved; the multi-element interpenetrating binder is strong in structural property and high in binding degree, the main chain of polyethylene glycol keeps original flexibility, a film layer is changed into a cross-linked network from loose filling through the cross-linking effect of maleic anhydride groups, polyvinyl alcohol is combined with rich hydroxyl groups which are rich, the polyvinyl alcohol and a passive film formed on the surface of iron powder can directly form hydrogen bonds and coordinate bonds, and therefore the binding effect of the iron powder is improved. The bridge effect of a silane coupling agent is replaced, the step of additionally adding a coupling agent is omitted, the process is simplified, the cost is reduced, the brittleness of a passive film is relieved, the porosity of a film layer is reduced, the film layer is prevented from cracking and falling off during mixing, and temperature resistance and water resistance are remarkably optimized.

Description

Technical Field

[0001] This invention belongs to the field of permanent magnet motor technology, specifically a wideband anti-interference wire harness composite magnetic ring and its preparation method. Background Technology

[0002] Permanent magnet motors generate their magnetic field using permanent magnets, thus eliminating the need for excitation current. Compared to traditional induction motors, they have a simpler structure, are more reliable, and offer significant advantages such as small size, light weight, low loss, and high efficiency. They are widely used in transportation, aviation, defense, industry, and daily life. In recent years, with increasing global attention to environmental issues caused by the greenhouse effect, the demand for energy efficiency in various motors has risen, driving the development of motors towards miniaturization, lightweight design, and high efficiency. In permanent magnet motors, the performance of the magnetic material is crucial to the motor's structural design and final performance. Under the same winding parameters and testing conditions, higher-performance magnetic materials result in higher maximum torque and higher efficiency at the peak efficiency point. Furthermore, for a given power permanent magnet motor, using higher-performance magnetic materials can reduce the number of winding turns, thus reducing the motor's size.

[0003] On the other hand, the magnitude of the air gap magnetic field in a permanent magnet motor is closely related to the shape, size (surface area and thickness), magnetization method, and magnetic coupling structure of the permanent magnet used. Even with magnetic materials of the same performance, different magnetic circuit designs will result in completely different air gap magnetic field magnitudes. Therefore, how to adopt a suitable magnetic circuit structure to fully utilize the performance of magnetic materials is also a hot research topic in the field of motors.

[0004] Chinese patent CN107959361A discloses a stator for a permanent magnet torque motor. By sealing the slots between the stator teeth with a sealing material, the stator teeth form a ring-shaped integral structure, while the stator yoke forms another integral structure. These two structures are separable, allowing the armature windings to be directly connected during stator assembly by inserting or snapping them together after mounting the armature windings onto the corresponding stator teeth. Furthermore, using nanocrystalline soft magnetic alloys or high-grade silicon steel for the stator core helps reduce motor losses. When the rotor permanent magnets support the core, and tangentially and radially magnetized permanent magnets are alternately arranged on the working air gap side surface of the core, the motor torque density is improved.

[0005] Chinese patent publication CN111164867A discloses a permanent magnet carrier comprising a first non-magnetic ring and a second non-magnetic ring. Soft magnetic pole elements are positioned between the rings, each connected to both the first and second non-magnetic rings, and are separated from each other by the first and second non-magnetic rings. A permanent magnet is disposed between the soft magnetic pole elements.

[0006] Chinese patent announcement CN115036092B discloses a composite magnetic ring and its preparation method. The method involves preparing a surface treatment solution containing polyethylene glycol, stirring iron powder in the surface treatment solution, and then adding PA12 powder and silane coupling agent for treatment. In this scheme, polyethylene glycol has good flexibility but poor stability, while PA12 has strong rigidity but insufficient toughness. Furthermore, the two have a large difference in polarity, which easily leads to interfacial delamination, resulting in poor coating ability on the surface of iron powder. Summary of the Invention

[0007] The purpose of this invention is to provide a broadband anti-interference wire harness composite magnetic ring and its preparation method. Using ferric oxide, manganese tetroxide and zinc oxide as raw materials, and with the action of a multi-element interpenetrating binder, it can absorb broadband interference signals and achieve synergy between anti-interference and magnetic properties.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] A method for preparing a broadband anti-interference wire harness composite magnetic ring includes the following steps:

[0010] Step 1: Styrene-maleic anhydride copolymer is obtained by hydrolyzing styrene-maleic anhydride copolymer under concentrated hydrochloric acid; modified polyethylene glycol copolymer is prepared by esterifying vinyl polyethylene glycol with styrene-maleic anhydride copolymer.

[0011] Step 2: The modified polyethylene glycol copolymer, castor oil maleate, polyvinyl alcohol and vinyl acetate are copolymerized under an initiator to obtain a multi-component interpenetrating adhesive.

[0012] Step 3: Mix ferric oxide, manganese tetroxide, and zinc oxide evenly, feed them into a vibratory mill for strong mixing, transfer them to a granulator to make the mixed powder cylindrical, and calcine to obtain coarse material; stir and mix the coarse material, multi-element interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate, spray granulate, and injection mold to obtain a broadband anti-interference wire harness composite magnetic ring.

[0013] Furthermore, the mass ratio of ferric oxide, manganese tetroxide, and zinc oxide is 42-45:32-35:18-20.

[0014] Furthermore, the ratio of coarse material, multi-component interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate is 90-92 kg: 450-455 g: 100-110 g: 100-110 g.

[0015] Furthermore, the specific preparation steps of the styrene-maleic acid copolymer are as follows:

[0016] The styrene-maleic anhydride copolymer and tetrahydrofuran were added to a reactor and stirred for 20-30 minutes at 20-25°C and 400-500 r / min. Then, concentrated hydrochloric acid with a mass fraction of 36.5-37.2% was added, and the mixture was heated to 55-60°C and reacted for 12-14 hours. Deionized water was then added to precipitate the polymer. The precipitate was filtered and washed 2-3 times with deionized water and anhydrous ethanol, respectively. The product was then freeze-dried at -40°C to obtain the styrene-maleic anhydride copolymer.

[0017] Furthermore, the ratio of styrene-maleic anhydride copolymer, tetrahydrofuran, concentrated hydrochloric acid, and deionized water is 400-500g: 5-L: 50-70mL: 7-8L.

[0018] Furthermore, the specific preparation steps of the modified polyethylene glycol copolymer are as follows:

[0019] Vinyl polyethylene glycol, styrene-maleic acid copolymer, triethylamine and toluene were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 400-500 r / min. Then the mixture was heated to 85-90℃ and stirred for 12-14 h under a nitrogen atmosphere. After natural cooling to room temperature, anhydrous diethyl ether was added to precipitate the polymer. The precipitate was filtered and washed 2-3 times with deionized water and anhydrous ethanol, respectively. The product was then freeze-dried at -40℃ to obtain the modified polyethylene glycol copolymer.

[0020] Furthermore, the ratio of vinyl polyethylene glycol, styrene-maleic acid copolymer, triethylamine and toluene is 300-400g: 500-700g: 20-30mL: 10-12L.

[0021] Furthermore, the specific preparation steps of the multi-element interpenetrating adhesive are as follows:

[0022] Modified polyethylene glycol copolymer, castor oil maleate, and deionized water are added to a reactor and stirred for 20-30 minutes at 20-25℃ and 400-500 rpm. Then, polyvinyl alcohol is added, and the mixture is heated to 70-80℃ and stirred until the material is completely dissolved. The temperature is then lowered to 40-45℃, and octylphenol polyoxyethylene ether is added as an emulsifier. The mixture is stirred for another 30-40 minutes. Then, vinyl acetate and potassium persulfate are added as initiators. The mixture is heated to 60-65℃ and kept at this temperature for 1-2 hours. The temperature is then lowered to 40-45℃, and sodium bicarbonate is added to adjust the pH to 6-7. Finally, dibutyl phthalate is added as a plasticizer, and the mixture is stirred for another 40-50 minutes. The mixture is then allowed to cool naturally and discharged to obtain a multi-component interpenetrating adhesive.

[0023] Furthermore, the ratio of modified polyethylene glycol copolymer, castor oil maleate, deionized water, polyvinyl alcohol, octylphenol polyoxyethylene ether, vinyl acetate, potassium persulfate, and dibutyl phthalate is 200-300g: 250-260mL: 800-900mL: 50-60mL: 1-2g: 20-30mL: 1-2g: 1-2g.

[0024] Furthermore, the specific fabrication steps of the broadband anti-interference wire harness composite magnetic ring are as follows:

[0025] Ferric oxide, manganese tetroxide, and zinc oxide are mixed evenly and fed into a vibratory mill for strong mixing to obtain a mixed powder with an average particle size of 1.1 μm. The powder is then transferred to a granulator, and the rolling pressure is adjusted to 8 MPa to make the rolled mixed powder cylindrical. It is then transferred again to a rotary kiln and heated to 900-920℃ for 1-2 hours to pulverize it to an average particle size of 1.0 μm to obtain coarse material. The coarse material, multi-element interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate are stirred for 10-12 minutes. The mixture is then spray-granulated at an inlet temperature of 300-320℃ and an outlet temperature of 150-170℃, and injection molded to obtain a broadband anti-interference wire harness composite magnetic ring.

[0026] The beneficial effects of this invention are:

[0027] 1. The broadband anti-interference wire harness composite magnetic ring prepared by the present invention uses ferric oxide, manganese tetroxide and zinc oxide as raw materials. Under the action of a multi-element interpenetrating binder, it can absorb broadband interference signals and achieve synergy between anti-interference and magnetic properties.

[0028] 2. The multi-component interpenetrating binder prepared in this invention involves double-bonding the long chains of castor oil, which has flexibility and hydrophobicity. This is achieved by copolymerizing a styrene-maleic anhydride copolymer with double-bonded vinyl polyethylene glycol, castor oil maleate, polyvinyl alcohol, and vinyl acetate. The resulting multi-component interpenetrating binder exhibits strong structure and high adhesion. The polyethylene glycol backbone retains its original flexibility, and the cross-linking effect of the maleic anhydride groups transforms the film layer from a loose filler to a cross-linked network. Combined with the abundant hydroxyl groups in polyvinyl alcohol, it can directly form hydrogen bonds and coordination bonds with the passivation film formed on the iron powder surface, replacing the bridging role of silane coupling agents. This eliminates the need for additional coupling agents, simplifies the process, and reduces costs. It alleviates the brittleness of the passivation film, reduces film porosity, prevents film cracking and detachment during mixing, and significantly optimizes temperature and water resistance.

[0029] 3. The linear segments of polyvinyl alcohol enhance the toughness and tensile strength of the binder, while the long chains of castor oil provide flexibility. The rigid segments of styrene-maleic anhydride strengthen the structural strength, and the copolymerization of vinyl acetate reduces internal stress, allowing the soft magnetic composite material to maintain stable mechanical strength after injection molding. In the interpenetrating network, the copolymer segments of polyvinyl alcohol and vinyl acetate enhance the heat resistance of the system, while the lubricating effect of the long chains of castor oil reduces frictional resistance during twin-screw mixing and improves processing fluidity. The multi-component interpenetrating binder provides more uniform coating of iron powder, reducing magnetic permeability fluctuations caused by iron powder aggregation. At the same time, the dense interpenetrating structure isolates air, and together with the passivation film, further inhibits the oxidation of iron powder at high temperatures, protecting its saturation magnetization from loss. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0031] Example 1: A method for preparing a broadband anti-interference wire harness composite magnetic ring, comprising the following steps:

[0032] S1: Add 400g of styrene-maleic anhydride copolymer and 5L of tetrahydrofuran to a reactor, stir for 20min at 20℃ and 400r / min, then add 50mL of concentrated hydrochloric acid with a mass fraction of 36.5%, heat to 55℃, and continue to react for 12h. Then add 7L of deionized water to precipitate the polymer, filter, wash the precipitate twice with deionized water and anhydrous ethanol, and freeze-dry the product at -40℃ to obtain styrene-maleic anhydride copolymer.

[0033] S2: Add 300g of vinyl polyethylene glycol, 500g of styrene-maleic acid copolymer, 20mL of triethylamine and 10L of toluene to a reactor. Stir for 20min at 20℃ and 400r / min, then heat to 85℃ and continue stirring for 12h under a nitrogen atmosphere. Allow to cool naturally to room temperature, add anhydrous diethyl ether to precipitate the polymer, filter, wash the precipitate twice with deionized water and anhydrous ethanol respectively, and freeze-dry the product at -40℃ to obtain the modified polyethylene glycol copolymer.

[0034] S3: Add 200g of modified polyethylene glycol copolymer, 250mL of castor oil maleate, and 800mL of deionized water to a reactor. Stir for 20min at 20℃ and 400r / min. Then add 50mL of polyvinyl alcohol, heat to 70℃, and stir until the material is completely dissolved. Then cool to 40℃, add 1g of octylphenol polyoxyethylene ether as an emulsifier, and continue stirring for 30min. Then add 20mL of vinyl acetate and 1g of potassium persulfate as an initiator, heat to 60℃, keep warm for 1h, cool to 40℃, add sodium bicarbonate to adjust the pH to 6, and then add 1g of dibutyl phthalate plasticizer. Continue stirring for 40min, cool naturally, and discharge to obtain a multi-component interpenetrating adhesive.

[0035] S4: Mix 42kg of ferric oxide, 32kg of manganese tetroxide and 18kg of zinc oxide evenly, and feed them into a vibratory mill for strong mixing to obtain a mixed powder with an average particle size of 1.1μm. Transfer the powder to a granulator, adjust the rolling pressure to 8MPa to make the rolled mixed powder cylindrical, and then transfer it to a rotary kiln to be heated to 900℃ and calcined for 1 hour. Crush the powder to an average particle size of 1.0μm to obtain coarse material. Stir 90kg of coarse material, 450g of multi-element interpenetrating binder, 100g of defoamer polyoxyethylene polyoxypropylene ether and 100g of dispersant sodium hexametaphosphate for 10 minutes. Spray granulate at an inlet temperature of 300℃ and an outlet temperature of 150℃, and injection mold to obtain a broadband anti-interference wire harness composite magnetic ring.

[0036] Example 2: A method for preparing a broadband anti-interference wire harness composite magnetic ring, comprising the following steps:

[0037] S1: 450g of styrene-maleic anhydride copolymer and 5L of tetrahydrofuran were added to a reactor and stirred for 25min at 22.5℃ and 450r / min. Then, 60mL of concentrated hydrochloric acid with a mass fraction of 36.85% was added, and the mixture was heated to 57.5℃ and reacted for 13h. Then, 7.5L of deionized water was added to precipitate the polymer. The precipitate was filtered and washed 2.5 times with deionized water and anhydrous ethanol, respectively. The product was freeze-dried at -40℃ to obtain the styrene-maleic anhydride copolymer.

[0038] S2: 350g of vinyl polyethylene glycol, 600g of styrene-maleic acid copolymer, 25mL of triethylamine and 11L of toluene were added to a reaction vessel and stirred for 25min at 22.5℃ and 450r / min. Then the mixture was heated to 87.5℃ and stirred for 13h under a nitrogen atmosphere. After cooling naturally to room temperature, anhydrous diethyl ether was added to precipitate the polymer. The precipitate was filtered and washed 2.5 times each with deionized water and anhydrous ethanol. The product was then freeze-dried at -40℃ to obtain the modified polyethylene glycol copolymer.

[0039] S3: Add 250g of modified polyethylene glycol copolymer, 255mL of castor oil maleate, and 850mL of deionized water to a reactor. Stir for 25min at 22.5℃ and 450r / min. Then add 55mL of polyvinyl alcohol, heat to 75℃, and stir until the material is completely dissolved. Then cool to 42.5℃, add 1.5g of octylphenol polyoxyethylene ether as an emulsifier, and continue stirring for 35min. Then add 25mL of vinyl acetate and 1.5g of potassium persulfate as an initiator, heat to 62.5℃, keep at this temperature for 1.5h, cool to 42.5℃, add sodium bicarbonate to adjust the pH to 6.5, and then add 1.5g of dibutyl phthalate plasticizer. Continue stirring for 45min, cool naturally, and discharge to obtain a multi-component interpenetrating adhesive.

[0040] S4: Mix 43.5 kg of ferric oxide, 33.5 kg of manganese tetroxide, and 19 kg of zinc oxide evenly, and feed them into a vibratory mill for strong mixing to obtain a mixed powder with an average particle size of 1.1 μm. Transfer the powder to a granulator, adjust the rolling pressure to 8 MPa to make the rolled mixed powder cylindrical, and then transfer it to a rotary kiln to be heated to 910℃ and calcined for 1.5 h. Crush the powder to an average particle size of 1.0 μm to obtain coarse material. Mix 91 kg of coarse material, 452.5 g of multi-element interpenetrating binder, 105 g of defoamer polyoxyethylene polyoxypropylene ether, and 105 g of dispersant sodium hexametaphosphate for 11 min. Spray granulate at an inlet temperature of 310℃ and an outlet temperature of 160℃, and injection mold to obtain a broadband anti-interference wire harness composite magnetic ring.

[0041] Example 3: A method for preparing a broadband anti-interference wire harness composite magnetic ring, comprising the following steps:

[0042] S1: Add 500g of styrene-maleic anhydride copolymer and 5L of tetrahydrofuran to a reactor, stir for 30min at 25℃ and 500r / min, then add 70mL of concentrated hydrochloric acid with a mass fraction of 37.2%, heat to 60℃, and continue the reaction for 14h. Then add 8L of deionized water to precipitate the polymer, filter, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and freeze-dry the product at -40℃ to obtain styrene-maleic anhydride copolymer.

[0043] S2: Add 400g of vinyl polyethylene glycol, 700g of styrene-maleic acid copolymer, 30mL of triethylamine and 12L of toluene to a reactor. Stir for 30min at 25℃ and 500r / min, then heat to 90℃ and continue stirring for 14h under a nitrogen atmosphere. Allow to cool naturally to room temperature, add anhydrous diethyl ether to precipitate the polymer, filter, wash the precipitate three times with deionized water and anhydrous ethanol respectively, and freeze-dry the product at -40℃ to obtain the modified polyethylene glycol copolymer.

[0044] S3: Add 300g of modified polyethylene glycol copolymer, 260mL of castor oil maleate, and 900mL of deionized water to a reactor. Stir for 30min at 25℃ and 500r / min. Then add 60mL of polyvinyl alcohol, heat to 80℃, and stir until the material is completely dissolved. Then cool to 45℃, add 2g of octylphenol polyoxyethylene ether as an emulsifier, and continue stirring for 40min. Then add 30mL of vinyl acetate and 2g of potassium persulfate as an initiator, heat to 65℃, keep warm for 2h, cool to 45℃, add sodium bicarbonate to adjust the pH to 7, then add 2g of dibutyl phthalate plasticizer, and continue stirring for 50min. Allow to cool naturally and discharge to obtain a multi-component interpenetrating adhesive.

[0045] S4: Mix 45kg of ferric oxide, 35kg of manganese tetroxide and 20kg of zinc oxide evenly, and feed them into a vibratory mill for strong mixing to obtain a mixed powder with an average particle size of 1.1μm. Transfer the powder to a granulator, adjust the rolling pressure to 8MPa to make the rolled mixed powder cylindrical, and then transfer it to a rotary kiln to be heated to 920℃ and calcined for 2 hours. Crush the powder to an average particle size of 1.0μm to obtain coarse material. Stir 92kg of coarse material, 455g of multi-element interpenetrating binder, 110g of defoamer polyoxyethylene polyoxypropylene ether and 110g of dispersant sodium hexametaphosphate for 12 minutes. Spray granulate at an inlet temperature of 320℃ and an outlet temperature of 170℃, and injection mold to obtain a broadband anti-interference wire harness composite magnetic ring.

[0046] Comparative Example 1: Based on Example 3, maleic ricinoleate in step S5 was replaced with commercially available ricinoleic acid.

[0047] Comparative Example 2: Based on Example 3, the modified polyethylene glycol copolymer in step S3 was replaced with the vinyl polyethylene glycol in step S2.

[0048] Comparative Example 3: Based on Example 3, the multi-component interpenetrating adhesive in step S4 was replaced with a mixture of polyethylene glycol and PA12.

[0049] At 23℃, the average surface magnetic intensity of the broadband anti-interference wire harness composite magnetic rings prepared in Examples 1-3 and Comparative Examples 1-3 was tested using a three-dimensional surface magnetic field tester. The results are shown in Table 1.

[0050] Table 1

[0051] project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Test standards / methods Average surface magnetic field strength (Gs) 3390 3428 3498 2985 2862 2915 Three-dimensional surface magnetic tester Permeability (μ, 25℃ / 1kHz) 756 782 800 648 575 592 GB / T 3658-2008 Saturation magnetization (Ms, T) 1.72 1.76 1.80 1.48 1.41 1.45 GB / T 13012-2008 Wideband interference attenuation (1MHz-1GHz) (dB) 32 33 35 22 18 20 Network Analyzer Testing Tensile strength (MPa) 10.5 11.3 12.1 7.2 6.3 6.8 GB / T 1040.3-2006

[0052] As shown in Table 1, in Comparative Example 1, maleic ricinoleate was replaced with commercially available ricinoleic acid in step S5. However, ricinoleic acid lacks a double bond structure and cannot copolymerize with vinyl polyethylene glycol or vinyl acetate. This results in the binder being merely a physical mixture rather than an interpenetrating network structure, leading to uneven coating of iron powder, easy aggregation and accelerated oxidation, decreased magnetic permeability, decreased saturation magnetization, decreased average surface magnetic intensity, and a broadband anti-interference attenuation of only 22 dB, failing to achieve broadband interference signal absorption. Furthermore, the lack of the flexibility provided by the long chains of castor oil significantly increases the brittleness of the binder, resulting in a tensile strength of only 7.2 MPa. The absence of a cross-linked network formed by copolymerization leads to high film porosity, making it prone to cracking and detachment at high temperatures, thus failing to meet the operating temperature requirements of the wire harness magnetic ring.

[0053] Comparative Example 2 replaced the modified polyethylene glycol copolymer with vinyl polyethylene glycol. Vinyl polyethylene glycol is a single flexible segment, lacking the rigid segments and cross-linking effects of styrene-maleic anhydride. The binder cannot form a dense coating film, and the oxide layer on the surface of the iron powder cannot be effectively isolated. The magnetic permeability is only 575 H / m, the saturation magnetization is 1.41 T, and the broadband anti-interference attenuation is 18 dB. It is completely unable to achieve the synergistic effect of strong magnetic field confinement and broadband anti-interference. The film layer degenerates from a cross-linked network to a loose filler. Due to the high frictional resistance during mixing, the processing fluidity is poor. The tensile strength is only 6.3 MPa, and cracks are prone to occur after injection molding, which cannot meet the mechanical structure requirements of the magnetic ring.

[0054] Comparative Example 3 replaced the multi-component interpenetrating binder with a mixture of polyethylene glycol and PA12. This mixture lacked an interpenetrating network structure, resulting in uneven coating of iron powder. Furthermore, it lacked the hydroxyl and maleic anhydride groups of polyvinyl alcohol, making it unable to form hydrogen bonds and coordination bonds with the passivation film. This resulted in weak interfacial adhesion, a magnetic permeability of 592 H / m, a saturation magnetization of 1.45 T, an average surface magnetic intensity of 2915 Gs, and an anti-interference attenuation of 20 dB. Lacking the softness of castor oil and the toughness of polyvinyl alcohol, the mixed binder was brittle, with a tensile strength of 6.8 MPa. It failed to alleviate the brittleness of the passivation film, leading to easy cracking and detachment of the film during mixing, resulting in exposed iron powder oxidation. Polyethylene glycol and PA12 showed poor compatibility, easily delaminating during mixing. Neither could replace the bridging effect of the silane coupling agent; in practical use, additional coupling agent was required to ensure basic adhesion, increasing costs.

[0055] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A method for preparing a broadband anti-interference wire harness composite magnetic ring, characterized in that, Includes the following steps: Step 1: Styrene-maleic anhydride copolymer is obtained by hydrolyzing styrene-maleic anhydride copolymer under concentrated hydrochloric acid; modified polyethylene glycol copolymer is prepared by esterification of styrene-maleic anhydride copolymer with vinyl polyethylene glycol. Step 2: The modified polyethylene glycol copolymer, castor oil maleate, polyvinyl alcohol and vinyl acetate are copolymerized under an initiator to obtain a multi-component interpenetrating adhesive; Step 3: Mix ferric oxide, manganese tetroxide, and zinc oxide evenly, feed them into a vibratory mill for strong mixing, transfer them to a granulator to make the mixed powder cylindrical, and calcine to obtain coarse material; stir and mix the coarse material, multi-element interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate, spray granulate, and injection mold to obtain a broadband anti-interference wire harness composite magnetic ring.

2. The method for preparing a broadband anti-interference wire harness composite magnetic ring according to claim 1, characterized in that, The mass ratio of ferric oxide, manganese tetroxide and zinc oxide is 42-45:32-35:18-20.

3. The method for preparing a broadband anti-interference wire harness composite magnetic ring according to claim 1, characterized in that, The ratio of the coarse material, multi-component interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate is 90-92 kg: 450-455 g: 100-110 g: 100-110 g.

4. The method of claim 1, wherein the method further comprises the steps of: providing a plurality of magnetic material pieces; and assembling the plurality of magnetic material pieces into a plurality of magnetic material segments. The specific preparation steps of the styrene-maleic acid copolymer are as follows: The styrene-maleic anhydride copolymer and tetrahydrofuran were added to a reactor and stirred for 20-30 minutes at 20-25°C and 400-500 r / min. Then, concentrated hydrochloric acid with a mass fraction of 36.5-37.2% was added, and the mixture was heated to 55-60°C and reacted for 12-14 hours. Deionized water was then added to precipitate the polymer. The precipitate was filtered and washed 2-3 times with deionized water and anhydrous ethanol, respectively. The product was then freeze-dried at -40°C to obtain the styrene-maleic anhydride copolymer.

5. The method of claim 4, wherein the method further comprises the step of: The ratio of the styrene-maleic anhydride copolymer, tetrahydrofuran, concentrated hydrochloric acid, and deionized water is 400-500g: 5-L: 50-70mL: 7-8L. ​ 6. The method of claim 1, wherein the method further comprises the steps of: providing a plurality of magnetic wires; and winding the plurality of magnetic wires around the core to form the composite magnetic ring. The specific preparation steps of the modified polyethylene glycol copolymer are as follows: Vinyl polyethylene glycol, styrene-maleic acid copolymer, triethylamine and toluene were added to a reaction vessel and stirred for 20-30 min at 20-25℃ and 400-500 r / min. Then the mixture was heated to 85-90℃ and stirred for 12-14 h under a nitrogen atmosphere. After natural cooling to room temperature, anhydrous diethyl ether was added to precipitate the polymer. The precipitate was filtered and washed 2-3 times with deionized water and anhydrous ethanol, respectively. The product was freeze-dried at -40℃ to obtain the modified polyethylene glycol copolymer. The ratio of the amount of vinyl polyethylene glycol, styrene-maleic acid copolymer, triethylamine and toluene is 300-400g: 500-700g: 20-30mL: 10-12L.

7. The method of claim 1, wherein the method further comprises the steps of: providing a plurality of magnetic wires; and winding the plurality of magnetic wires around the core to form the composite magnetic ring. The specific preparation steps of the multi-element interpenetrating adhesive are as follows: Modified polyethylene glycol copolymer, castor oil maleate, and deionized water are added to a reactor and stirred for 20-30 minutes at 20-25℃ and 400-500 rpm. Then, polyvinyl alcohol is added, and the mixture is heated to 70-80℃ and stirred until the material is completely dissolved. The temperature is then lowered to 40-45℃, and octylphenol polyoxyethylene ether is added as an emulsifier. The mixture is stirred for another 30-40 minutes. Then, vinyl acetate and potassium persulfate are added as initiators. The mixture is heated to 60-65℃ and kept at this temperature for 1-2 hours. The temperature is then lowered to 40-45℃, and sodium bicarbonate is added to adjust the pH to 6-7. Finally, dibutyl phthalate is added as a plasticizer, and the mixture is stirred for another 40-50 minutes. The mixture is then allowed to cool naturally and discharged to obtain a multi-component interpenetrating adhesive.

8. The method of claim 7, wherein the method further comprises the step of: The ratio of the modified polyethylene glycol copolymer, castor oil maleate, deionized water, polyvinyl alcohol, octylphenol polyoxyethylene ether, vinyl acetate, potassium persulfate, and dibutyl phthalate is 200-300g: 250-260mL: 800-900mL: 50-60mL: 1-2g: 20-30mL: 1-2g: 1-2g. ​ 9. The method of claim 1, wherein the method further comprises the steps of: providing a plurality of magnetic wires; and winding the plurality of magnetic wires around the core to form the composite magnetic ring. The specific preparation steps of the broadband anti-interference wire harness composite magnetic ring are as follows: Ferric oxide, manganese tetroxide, and zinc oxide are mixed evenly and fed into a vibratory mill for strong mixing to obtain a mixed powder with an average particle size of 1.1 μm. The powder is then transferred to a granulator, and the rolling pressure is adjusted to 8 MPa to make the rolled mixed powder cylindrical. It is then transferred again to a rotary kiln and heated to 900-920℃ for 1-2 hours to pulverize it to an average particle size of 1.0 μm to obtain coarse material. The coarse material, multi-element interpenetrating binder, defoamer polyoxyethylene polyoxypropylene ether, and dispersant sodium hexametaphosphate are stirred for 10-12 minutes. The mixture is then spray-granulated at an inlet temperature of 300-320℃ and an outlet temperature of 150-170℃, and injection molded to obtain a broadband anti-interference wire harness composite magnetic ring.

10. A broadband anti-interference wire harness composite magnetic ring, characterized in that, It is prepared by the preparation method described in any one of claims 1-9.