Wet granulation equipment based on soft magnetic powder and granulation method thereof

Abstract

The invention relates to the technical field of magnetic composite material preparation, in particular to a wet granulation method based on soft magnetic powder, which comprises the following steps: S1, powder pretreatment: mixing soft magnetic powder with a coupling agent to form a first mixture; s2, preparing a premixed solution, and mixing low-viscosity epoxy resin with a curing agent to form the premixed solution; s3, preparing a wet paste, and stirring and mixing the first mixture and the premixed liquid through a stirring mechanism to form a semi-wet paste; s4, extruding the granulated and uniformly stirred semi-wet paste into a crushing mechanism from the stirrer, primarily cutting the semi-wet paste by the crushing mechanism, extruding the semi-wet paste into strip-shaped particles through an arranged screen, forming soft magnetic powder through vacuum drying, adding a coupling agent into the soft magnetic powder to serve as a coating layer, improving the binding force of the soft magnetic powder, and then adding the coupling agent into the soft magnetic powder to serve as a coating layer; metal or nonmetal epoxy resin is effectively bonded together, and coating of the soft magnetic powder and the epoxy resin is improved.

Description

Technical Field

[0001] This invention belongs to the field of magnetic composite material preparation technology, specifically relating to wet granulation equipment and granulation method based on soft magnetic powder. Background Technology

[0002] In recent years, electronic communications and smart electronic products have developed rapidly, and with the popularization of big data analysis and 5G communication equipment, the frequency of information processing is getting higher and higher. Literature reviews from the past decade show that the operating frequency of electronic communication equipment has evolved from several hundred kHz to tens of MHz, and the processing frequency in big data processing equipment, 5G communication equipment, and military electronic equipment can reach over 100 MHz. Inductors are indispensable electromagnetic components in the circuits of computers and various information processing electronic devices.

[0003] Fe-based magnetic materials, with their advantages of high magnetic flux density and low coercivity, are widely used in the manufacture of inductors. Due to the proliferation of various information processing devices, such as computers, laptops, tablets, smartphones, automotive electronics, wireless charging, and electric vehicle charging stations, the application and manufacturing volume of inductors is exceeding expectations. However, due to the size limitations of these electronic devices, inductors must be miniaturized and operate at high frequencies; therefore, surface-mount molded (SMD) inductors have become the mainstream application type. Regardless of shape, surface-mount molded inductors are basically manufactured using two methods: in-coil molding (Molding Type) and out-of-coil sintering (NR Type). Regardless of the manufacturing process, the Fe-based soft magnetic powder must undergo insulation treatment. The significance of insulation treatment is to minimize charge concentration on the surface of powder particles under high-frequency AC electromagnetic fields, and to prevent eddy currents generated inside the powder particles from conducting between them (considered a short circuit). Otherwise, the inductor will experience significant power loss, heat generation, and even circuit burnout. Furthermore, it is essential to prevent the inductor from breaking down under instantaneous high voltage, which could damage the entire device.

[0004] In recent years, due to the stringent power loss control requirements of big data analytics, 5G communication equipment, and next-generation solid-state drives (SSDs) and ultra-high-frequency CPU integrated circuits at high frequencies, Fe-based amorphous powders, such as Fe-Si-BC types, and Fe-based nanocrystals, such as Fe-Si-B-Cu-Nb (Finemet), have gradually gained attention and are already being used to manufacture new low-loss inductors. The main types of Fe-based soft magnetic powders include: pure iron powder, Fe-Si, Fe-Si-Cr, Fe-Ni (Permalloy), Fe-Ni-Mo (MPP), Fe-Co, and Fe-Si-Al (SenduSt).

[0005] Currently, the preparation techniques for insulating layers of various Fe-based soft magnetic powders are mainly divided into inorganic coating insulation and organic coating insulation. Organic coating insulation uses organic solvents such as epoxy resin, phenolic resin, or silicone resin to coat the surface of the particles, and then heats and dries to form an organic-coated insulating layer.

[0006] Traditional mixed granulation may have the following problems: 1. Problems such as uneven resin distribution and powder agglomeration.

[0007] 2. Solvent pollution: Some wet processes require large amounts of organic solvents (such as acetone), increasing environmental protection and recycling costs.

[0008] 3. Heat-sensitive failure: Hot melt extrusion can easily lead to premature curing of epoxy resin, reducing the particle forming rate.

[0009] Therefore, wet granulation equipment and granulation methods based on soft magnetic powder are needed to solve the above problems. Summary of the Invention

[0010] To address the aforementioned technical problems, this invention provides a wet granulation device and granulation method based on soft magnetic powder, thereby resolving the existing market issues mentioned in the background section.

[0011] To achieve the above objectives, the technical solution of the present invention is as follows: Wet granulation methods based on soft magnetic powders include: S1. Powder pretreatment: soft magnetic powder is mixed with coupling agent to form a first mixture; S2. Prepare a premixed liquid by mixing low-viscosity epoxy resin with a curing agent to form a premixed liquid. S3. To prepare a wet paste, the first mixture and the premixed liquid are mixed by stirring with a stirring mechanism to form a semi-wet paste. S4. Granulation: The uniformly mixed semi-wet paste is extruded from the mixer into the crushing mechanism. The crushing mechanism performs preliminary cutting of the semi-wet paste and extrudes it into strip-shaped particles through a screen. The particles are then dried under vacuum to form soft magnetic powder.

[0012] Through the above technical solution, the coupling agent is first added to the soft magnetic powder to act as a coating layer, which improves the bonding force of the soft magnetic powder and effectively binds the metal or non-metal epoxy resin together, improving the coating performance of the soft magnetic powder and epoxy resin. The stirring mechanism further stirs the soft magnetic powder and epoxy resin evenly, and the crusher crushes the clumps of soft magnetic powder into a loose state and extrudes it from the screen, reducing the production process, shortening the manufacturing steps, and improving production efficiency.

[0013] As a preferred embodiment of the present invention, S1 further includes the following steps: S11. Pass the soft magnetic powder through a 500-mesh sieve; S12. Mix 80wt% soft magnetic powder with 0.5wt% coupling agent to form a first mixture, wherein the soft magnetic powder is iron-silicon-aluminum and the coupling agent is silane; S13. Mix and stir for 10 minutes.

[0014] The above technical solution involves first mixing soft magnetic powder that has passed through a 500-mesh sieve with 0.5wt% coupling agent until the mixture is uniformly stirred, so that the coupling agent is evenly coated on the surface of the soft magnetic powder particles, thereby increasing the bonding strength of the soft magnetic powder.

[0015] As a preferred embodiment of the present invention, the premixed liquid in step S2 further includes: 5 wt% epoxy resin EPON, 1 wt% polyamide 650, and 4% acetone solution.

[0016] As a preferred embodiment of the present invention, step S3 further includes stirring the premixed liquid and the first mixture at a ratio of 1:0.02-0.05 using a stirring mechanism for 10-30 minutes to form a semi-wet paste; As a preferred embodiment of the present invention, step S4 further includes the following steps: S41. The stirring mechanism in step S3 squeezes the semi-wet paste into the crushing mechanism; S42. The grinding mechanism rotates at 60 rpm, and the grinding mechanism controls the mixing temperature between 0-15℃ through the cooling mechanism. S43. The crushing mechanism extrudes the semi-wet paste into strip-shaped particles through a screen at the discharge port. The screen is 50-500 mesh. S44. The strip-shaped particles are further dispersed at the discharge port of the crushing mechanism by a blower mechanism; S45. Place the strip-shaped particles from step S44 into a vacuum environment and dry for 30 minutes to form soft magnetic powder.

[0017] Through the above technical solution, the crushing mechanism crushes the clumps of soft magnetic powder to avoid agglomeration. At the same time, the cooling mechanism controls the temperature between 0-15℃ to inhibit premature curing caused by the exothermic reaction of epoxy resin. The mesh screen controls the aspect ratio of the soft magnetic powder particles, and the blower mechanism further disperses the strip-shaped particles, reducing the drying time and preventing particle agglomeration. The powder is then dried and volatilized in a vacuum environment to form soft magnetic powder.

[0018] A wet granulation apparatus based on soft magnetic powder, comprising: The mixing mechanism includes a mixing tank with a cavity, a Z-shaped mixing shaft located in the middle of the mixing tank, an extrusion mixing shaft located in the lower part of the mixing tank, and a drive assembly one and a drive assembly two for driving the Z-shaped mixing shaft and the extrusion mixing shaft respectively. The output end of the extrusion mixing shaft is an extrusion port. The crushing mechanism includes a discharge barrel located at the extrusion port via a feed hopper, a screw propeller located inside the discharge barrel, a cutter head located at the output end of the screw propeller, a screen located at the discharge port, and a cooling mechanism located on the outer periphery of the discharge barrel, wherein the discharge barrel is surrounded by an outer barrel, and a sandwich cavity is provided between the outer barrel and the discharge barrel.

[0019] Through the above technical solution, the Z-shaped stirring shaft stirs the first mixture in the semi-wet paste and the premixed liquid evenly. The extrusion stirring shaft extrudes the stirred semi-wet paste into the pulverizer for further pulverization and dispersion. While pulverizing, the pulverizing mechanism controls the temperature between 0-15℃ through the cooling mechanism to inhibit premature curing caused by the exothermic reaction of epoxy resin. The aspect ratio of the soft magnetic powder particles is controlled by the screen. The blower mechanism further disperses the strip-shaped particles, reduces the subsequent drying time, and avoids particle agglomeration. The powder is then dried and volatilized in a vacuum environment to form soft magnetic powder.

[0020] As a preferred embodiment of the present invention, the surface of the cutter head is coated with a hard ceramic layer, and the material of the hard ceramic layer is Al2O3-ZrO2.

[0021] The above technical solution allows the hard ceramic layer to break up the semi-wet paste without damaging it. Using a regular blade could cause the well-bonded soft magnetic powder to be cut and lose its insulation.

[0022] As a preferred embodiment of the present invention, the cooling mechanism includes a condensation pipe spirally wound within the jacket of the discharge barrel, and a refrigeration chip disposed at the inlet of the condensation pipe.

[0023] Through the above technical solution, the cooling chip cools the condensate in the condensation pipe, preventing the epoxy resin from curing prematurely due to the heat generated during the operation of the mixer.

[0024] As a preferred embodiment of the present invention, the screen aperture is 0.5-3mm.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows: The coupling agent is first added to the soft magnetic powder to act as a coating layer, which improves the bonding force of the soft magnetic powder and effectively binds the metal or non-metal epoxy resin together, improving the coating properties of the soft magnetic powder and epoxy resin. The stirring mechanism further mixes the soft magnetic powder and epoxy resin evenly, and the crusher crushes the clumps of soft magnetic powder into a loose state and extrudes it from the screen, reducing the production process, shortening the manufacturing steps, and improving production efficiency. The shredder features high shear force, continuous feeding, and low-temperature operation. Through structural improvements, it can be adapted to the wet granulation requirements of magnetic composite materials, achieving low-cost and high-efficiency production. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the wet granulation equipment of the present invention; Figure 2 A schematic diagram of the molecular formula of soft magnetic powder in the prior art; Figure 3 This is a schematic diagram of the molecular formula of the soft magnetic powder of the present invention. Detailed Implementation

[0028] The present invention provides the following embodiments: A wet granulation method based on soft magnetic powder 3 includes: S1. Powder pretreatment: Soft magnetic powder 3 is mixed with coupling agent 4 to form a first mixture; S1 also includes the following steps: S11. Pass the soft magnetic powder through a 500-mesh sieve. S12. Mix 80wt% soft magnetic powder 3 with 0.5wt% coupling agent 4 to form a first mixture, wherein the soft magnetic powder 3 is iron-silicon-aluminum and the coupling agent 4 is silane. S13. Mix and stir for 10 minutes.

[0029] First, the soft magnetic powder 3 that has passed through a 500-mesh sieve 25 is mixed evenly with 0.5wt% coupling agent 4. The mixture is stirred evenly so that the coupling agent 4 is evenly coated on the surface of the soft magnetic powder 3 particles, thereby increasing the bonding strength of the soft magnetic powder 3. The coupling agent 4 is added to the soft magnetic powder 3 first, acting as a coating layer to improve the bonding strength of the soft magnetic powder 3, effectively making the metal or non-metal epoxy resin 5 bond together, and improving the coating performance of the soft magnetic powder 3 and epoxy resin 5.

[0030] S2. Prepare a premixed liquid by mixing low-viscosity epoxy resin 5 with a curing agent to form a premixed liquid. S3. To prepare a wet paste, the first mixture and the premixed liquid are mixed by stirring mechanism 1 to form a semi-wet paste. S4. Granulation: The uniformly stirred semi-wet paste is squeezed from the mixer into the crushing mechanism 2. The crushing mechanism 2 performs preliminary cutting of the semi-wet paste and squeezes it out into strip-shaped particles through the set screen 25. The soft magnetic powder 3 is formed by vacuum drying for 30 minutes. Step S4 also includes the following steps: S41. In step S3, the stirring mechanism 1 squeezes the semi-wet paste into the crushing mechanism 2; S42. The grinding mechanism 2 rotates at 60 rpm, and the grinding mechanism 2 controls the stirring temperature between 0-15℃ through the cooling mechanism. S43, The crushing mechanism 2 extrudes the semi-wet paste into strip-shaped particles through the screen at the discharge port. The screen is 50-500 mesh. S44. The strip-shaped particles are further dispersed at the discharge port of the crushing mechanism 2 by a blower mechanism. S45. Place the strip-shaped particles from step S44 into a vacuum environment and dry for 30 minutes to form soft magnetic powder 3.

[0031] The crushing mechanism 2 crushes the clumps of soft magnetic powder 3 to prevent agglomeration. At the same time, the cooling mechanism controls the temperature between 0-15℃ to inhibit premature curing caused by the exothermic reaction of epoxy resin 5. The aspect ratio of the soft magnetic powder 3 particles is controlled by the screen. The blower mechanism further disperses the strip-shaped particles and reduces the subsequent drying time, also preventing particle agglomeration. The powder is dried and volatilized in a vacuum environment to form soft magnetic powder 3. The stirring mechanism 1 further mixes the soft magnetic powder 3 and epoxy resin 5 evenly. The crusher crushes the clumps of soft magnetic powder 3 into a loose state and extrudes it from the screen 25, reducing the production process, shortening the manufacturing steps, and improving production efficiency.

[0032] The premixed solution in step S2 also includes: 5 wt% epoxy resin 5EPON, 1 wt% polyamide 650, and 4% acetone solution, which greatly reduces the amount of acetone used.

[0033] Step S3 further includes mixing the premixed liquid and the first mixture at a ratio of 1:0.02-0.05 using the stirring mechanism 1 for 10-30 minutes to form a semi-wet paste; Performance Comparison index Traditional extrusion method The process of this invention Resin coating uniformity (tg weight loss) 0.2% 0.3% Process yield 80% 95% Particle aspect ratio 0.89 0.94 Particle True Density 6.67 6.78 Collapse intensity / N 300 369 Magnetic loss (100kHz) 320 298 A wet granulation apparatus based on soft magnetic powder 3, comprising: The stirring mechanism 1 includes a stirring tank 11 with a cavity, a Z-shaped stirring shaft 12 located in the middle of the stirring tank 11, an extrusion stirring shaft 13 located in the lower part of the stirring tank 11, and a drive assembly 14 and a drive assembly 15 that drive the Z-shaped stirring shaft 12 and the extrusion stirring shaft 13 respectively. The output end of the extrusion stirring shaft 13 is an extrusion port. Drive assembly 14 and drive assembly 2 are drive motors. The Z-shaped stirring shaft 12 is arranged horizontally, vertically or obliquely inside the stirring tank 11. The extrusion port is circular and is located on the lower side of the stirring tank 11.

[0034] The crushing mechanism 2 includes a discharge barrel 22 located at the extrusion port via a feed hopper 21, a screw propeller 23 located inside the discharge barrel 22, a cutter head 24 located at the output end of the screw propeller 23, a screen 25 located at the discharge port, and a cooling mechanism located on the outer periphery of the discharge barrel 22. The discharge barrel 22 is covered by an outer barrel 221, and a sandwich cavity 222 is provided between the outer barrel 221 and the discharge barrel 22. The screen 25 has a mesh size of 0.5-3mm.

[0035] The Z-shaped stirring shaft 12 mixes the first mixture in the semi-wet paste with the premixed liquid evenly. The extrusion stirring shaft 13 extrudes the mixed semi-wet paste into the grinder for further grinding and dispersion. While grinding, the grinding mechanism 2 controls the temperature between 0-15℃ through the cooling mechanism to inhibit the premature curing caused by the exothermic reaction of epoxy resin 5. The aspect ratio of the soft magnetic powder 3 particles is controlled by the screen. The blower mechanism further disperses the strip-shaped particles, reduces the drying time in the later stage, and avoids particle agglomeration. The particles are dried and volatilized in a vacuum environment to form soft magnetic powder 3.

[0036] The blade 24 is coated with a hard ceramic layer, the material of which is Al2O3-ZrO2. The hard ceramic layer is beneficial for breaking up the semi-wet paste without damaging it. If an ordinary blade is used, the well-bonded soft magnetic powder 3 may be cut and lose its insulation.

[0037] The cooling mechanism includes a condensation pipe 26 spirally wound inside the jacket of the discharge barrel 22, and a cooling chip located at the input end of the condensation pipe 26. The cooling chip cools the condensate in the condensation pipe 26 to prevent the epoxy resin 5 from curing prematurely due to heat generated during the operation of the mixer.

[0038] The coupling agent 4 is first added to the soft magnetic powder 3 to act as a coating layer, which improves the bonding force of the soft magnetic powder 3 and effectively binds the metal or non-metal epoxy resin 5 together, improving the coating properties of the soft magnetic powder 3 and epoxy resin 5. The stirring mechanism 1 further stirs the soft magnetic powder 3 and epoxy resin 5 evenly. The crusher crushes the clumps of soft magnetic powder 3 into a loose state and extrudes it from the screen 25, reducing the production process, shortening the manufacturing steps, improving production efficiency, reducing the complexity of the production process and technology, and enabling better service and market expansion.

[0039] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A wet granulation method based on soft magnetic powder, characterized in that... ,include: S1. Powder pretreatment: soft magnetic powder is mixed with coupling agent to form a first mixture; S2. Prepare the premixed liquid by mixing epoxy resin and curing agent to form a premixed liquid; S3. To prepare a wet paste, the first mixture and the premixed liquid are mixed by stirring with a stirring mechanism to form a semi-wet paste. S4. Granulation: The uniformly stirred semi-wet paste is squeezed from the stirring mechanism into the crushing mechanism. The crushing mechanism performs preliminary cutting of the semi-wet paste and squeezes it out into strip-shaped particles through a screen. The particles are then dried under vacuum to form soft magnetic powder.

2. The wet granulation method based on soft magnetic powder according to claim 1, characterized in that, S1 also includes the following steps: S11. Pass the soft magnetic powder through a 500-mesh sieve; S12. Mix 70-100wt% soft magnetic powder with 0.3-0.8wt% coupling agent to form a first mixture, wherein the soft magnetic powder is any one or more of non-metallic iron powder, carbonyl iron powder, or alloy powder, and the coupling agent is silane. S13. Mix and stir for 10 minutes.

3. The wet granulation method based on soft magnetic powder according to claim 1, characterized in that, The premixed solution in step S2 also includes: 5 wt% epoxy resin EPON, 1 wt% polyamide 650, and 4% acetone solution.

4. The wet granulation method based on soft magnetic powder according to claim 1, characterized in that, Step S3 further includes mixing the premixed liquid and the first mixture at a ratio of 1:0.02-0.05 using a stirring mechanism for 10-30 minutes to form a semi-wet paste.

5. The wet granulation method based on soft magnetic powder according to claim 1, characterized in that, Step S4 also includes the following steps: S41. The stirring mechanism in step S3 extrudes the semi-wet paste into the grinding mechanism; S42. The grinding mechanism rotates at 60 rpm, and the grinding mechanism controls the stirring temperature between 0-15℃ through the cooling mechanism. S43. The crushing mechanism extrudes the semi-wet paste into strip-shaped particles through a screen at the discharge port. The screen is 50-500 mesh. S44. The strip-shaped particles are further dispersed at the discharge port of the crushing mechanism by a blower mechanism; S45. Place the strip-shaped particles from step S44 into a vacuum environment and dry for 30 minutes to form soft magnetic powder.

6. A wet granulation apparatus based on soft magnetic powder, comprising the wet granulation method based on soft magnetic powder as described in claims 1-6, characterized in that, include: The mixing mechanism includes a mixing tank with a cavity, a Z-shaped mixing shaft located in the middle of the mixing tank, an extrusion mixing shaft located in the lower part of the mixing tank, and a drive assembly one and a drive assembly two for driving the Z-shaped mixing shaft and the extrusion mixing shaft respectively. The output end of the extrusion mixing shaft is an extrusion port. The crushing mechanism includes a discharge barrel located at the extrusion port via a feed hopper, a screw propeller located inside the discharge barrel, a cutter head located at the output end of the screw propeller, a screen located at the discharge port, and a cooling mechanism located on the outer periphery of the discharge barrel.

7. The wet granulation equipment based on soft magnetic powder according to claim 6, characterized in that, The discharge hopper is fitted with an outer hopper, and there is a cavity between the outer hopper and the discharge hopper.

8. The wet granulation equipment based on soft magnetic powder according to claim 7, characterized in that, The blade surface is coated with a hard ceramic layer, the material of which is Al2O3-ZrO2.

9. The wet granulation equipment based on soft magnetic powder according to claim 8, characterized in that, The cooling mechanism includes a condensation pipe spirally wound inside the discharge barrel jacket, and a refrigeration chip located at the inlet of the condensation pipe.

10. The wet granulation equipment based on soft magnetic powder according to claim 7, characterized in that, The screen mesh size is 0.5-3mm.

Images