Step-by-step curing process for efficient anti-gelling impregnated magnetic powder core

Abstract

The invention discloses a step-by-step curing process for an efficient anti-gelling impregnated magnetic powder core, which comprises the following steps of: impregnating a molded magnetic powder core in an impregnation liquid added with a photosensitizer, firstly performing ultraviolet curing, and then performing heating curing. According to the curing process, the problem of glue discharge of the magnetic powder core in a traditional high-temperature heating curing process is successfully solved, the surface of the magnetic powder core treated through the curing process is smooth and flat, no redundant glue stain exists, the appearance quality of a product is greatly improved, the adverse effect of glue discharge on the internal structure and the electromagnetic property of the magnetic powder core is effectively avoided, and the service life of the magnetic powder core is prolonged. And it is ensured that the magnetic powder core can stably and efficiently work in electronic equipment.

Description

Technical Field

[0001] The invention belongs to the technical field of magnetic powder core processing, and in particular relates to a step-by-step curing process for an impregnated magnetic powder core with high efficiency and anti-glueing properties. Background Art

[0002] In the field of modern electronic equipment manufacturing, magnetic powder cores are key components and are widely used in various electronic devices. Their performance is directly related to the stability and reliability of electronic devices. To enhance the comprehensive performance of magnetic powder cores, curing after impregnation is a common process.

[0003] Traditional magnetic powder core curing processes often rely on a single, high-temperature heating method. While this method achieves a certain degree of curing effectiveness, it presents numerous drawbacks during actual production and application. The most prominent issue is the tendency for glue to bleed from the powder core during high-temperature curing. This bleed not only leaves the powder core surface uneven and with excess glue stains, severely impacting the product's appearance, but also negatively impacts the core's internal microstructure and electromagnetic properties. Excess glue alters the distribution of magnetic powder particles within the core, disrupting the proper conduction of the magnetic circuit and, consequently, affecting its proper operation in electronic devices, leading to reduced performance and stability.

[0004] With the rapid development of electronic technology, electronic devices are moving towards miniaturization and higher performance, and the quality and performance requirements for magnetic powder cores are becoming increasingly stringent. Traditional curing processes are no longer able to meet these growing demands. Therefore, developing a new magnetic powder core curing process that can overcome the glue release problem of traditional processes has become a key technical challenge that needs to be solved in the field of magnetic powder core processing. Summary of the Invention

[0005] The purpose of the present invention is to provide a step-by-step curing process for an impregnated magnetic powder core with high efficiency and anti-glue exudation, aiming to solve the problem of magnetic powder core exudation caused by the traditional high-temperature heating curing process, improve the quality and performance of the magnetic powder core, and meet the increasingly stringent requirements of electronic equipment for magnetic powder cores.

[0006] In order to solve the technical problem, the present invention adopts the following technical solution:

[0007] The invention discloses a step-by-step curing process for an efficient anti-glue impregnated magnetic powder core, which is characterized in that the formed magnetic powder core is impregnated in an impregnation liquid with a photosensitizer, firstly UV-cured, and then heated for curing.

[0008] Furthermore, the raw materials in the impregnation liquid are composed of the following by mass percentage: resin 40%-50%, curing agent 10%-14%, photosensitizer 2%-3%, solvent 35%-40%, coupling agent 1%-2%, and diluent 1%-2%. The impregnation liquid is composed of multiple substances with different functions, and the components work synergistically to ensure the curing quality of the magnetic powder core.

[0009] Furthermore, the resin is selected from epoxy resin, phenolic resin, unsaturated polyester resin, and silicone resin. Different resins offer unique performance advantages: epoxy resin has excellent adhesion and electrical insulation; phenolic resin has good heat resistance; unsaturated polyester resin cures quickly; and silicone resin offers excellent high-temperature and weather resistance. By properly selecting and combining resins, the diverse performance requirements of magnetic powder cores in different application scenarios can be met.

[0010] Furthermore, the curing agent is selected from at least one of an amine curing agent and an acid anhydride curing agent. The curing agent plays a vital role in the impregnation solution. It chemically reacts with the resin to promote crosslinking and curing of the resin molecular chains to form a stable three-dimensional network structure.

[0011] Furthermore, the photosensitizer is selected from one of benzoin ether photosensitizers, benzophenone or its derivatives, α-hydroxyketone photosensitizers, and thioxanthone photosensitizers. Under ultraviolet light irradiation, the photosensitizer can rapidly absorb photon energy, undergo a photochemical reaction, and generate free radicals. These free radicals act as initiators to trigger a polymerization reaction of the resin in the impregnation solution, achieving rapid curing.

[0012] Furthermore, the solvent is selected from at least one of ethylene glycol monomethyl ether, benzyl alcohol, tetrachloroethylene, and ethylene glycol diacetate. The solvent primarily regulates the viscosity of the impregnation solution, ensuring good fluidity and sufficient penetration into the pores of the magnetic powder core, ensuring uniform impregnation. The solvent also helps dissolve other raw material components, promoting uniform mixing among the ingredients and ensuring the stability of the impregnation solution.

[0013] Furthermore, the coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and isopropyl triisostearoyl titanate, and the diluent is selected from at least one of 1,4-butanediol diglycidyl ether and benzyl glycidyl ether. The coupling agent can enhance the interfacial bonding between the resin and the magnetic powder, improving the overall performance of the magnetic powder core; the diluent can adjust the viscosity of the impregnation solution and improve process operability.

[0014] Furthermore, a defoaming agent may be added to the impregnation liquid to eliminate bubbles generated during the preparation and use of the impregnation liquid, thereby avoiding adverse effects of bubbles on the performance of the magnetic powder core.

[0015] Furthermore, the formed magnetic powder core is immersed in the impregnation liquid for 30 to 60 minutes to allow the impregnation liquid to fully penetrate the pores of the magnetic powder core. After the impregnation is completed, the magnetic powder core is removed, cleaned, and air-dried.

[0016] The present invention adopts an innovative step-by-step curing method for the impregnated magnetic powder core, which mainly includes the following key steps:

[0017] UV curing stage: The impregnated magnetic powder core treated in the impregnation liquid is placed under ultraviolet light for irradiation. Under the action of ultraviolet light, the photosensitizer in the impregnation liquid quickly absorbs photon energy and produces a large number of free radicals. These free radicals trigger the rapid polymerization of the resin in the impregnation liquid to initially form a cured structure. This structure can effectively lock the impregnation liquid to prevent it from flowing and seeping out during subsequent treatment, laying a solid foundation for subsequent heating and curing. In actual operation, the wavelength, intensity and irradiation time of the ultraviolet light used are precisely selected according to the selected photosensitizer. For example, for benzoin ether photosensitizers, ultraviolet light in the wavelength range of 300-400nm has a better excitation effect, and the intensity of ultraviolet light is generally controlled at 5-30mW / cm 2 The irradiation time is usually 1 to 10 minutes. The specific parameters need to be adjusted comprehensively according to factors such as the size, shape, impregnation liquid formula and production efficiency of the magnetic powder core.

[0018] Curing Stage: After UV curing, the powder core is transferred to a heating device for curing. During the curing process, optimal temperature and time are controlled to further promote the complete curing of the impregnation liquid, enhancing the overall strength and stability of the powder core. Because the initial UV curing has established a solid foundation, the impregnation liquid within the powder core can continue to cure within a stable structural framework during the heating process, eliminating the glue extrusion common in traditional high-temperature curing processes. Curing temperatures are typically controlled in stages: the first curing temperature can be set at 80-150°C for 1-3 hours to achieve initial curing and further cross-linking of the impregnation liquid; the second curing temperature can be increased to 160-230°C for 1-3 hours to ensure complete curing of the impregnation liquid and achieve optimal performance. Specific temperature and time parameters can be optimized based on the powder core material, impregnation liquid formulation, and application requirements.

[0019] The beneficial effects of the present invention are embodied in:

[0020] 1. Significantly Improved Appearance Quality: This innovative curing process successfully overcomes the problem of glue release from magnetic powder cores encountered in traditional high-temperature curing processes. The resulting cores exhibit a smooth, even surface, free of excess glue stains. This significantly enhances the product's appearance and eliminates the need for additional glue treatment during electronic device assembly, improving assembly efficiency and enhancing the overall product quality.

[0021] 2. The performance optimization effect is obvious: the curing process of the present invention effectively avoids the adverse effects of glue discharge on the internal structure and electromagnetic properties of the magnetic powder core, ensuring that the magnetic powder core can work stably and efficiently in electronic equipment. From the data of the examples, compared with the impregnated magnetic powder core that has not been UV-cured, the breaking tensile strength of the samples of the present invention that have been dual-cured by UV and heating is significantly improved (for example, the breaking tensile strength of the samples of Examples 1 to 3 is 471.43%, 771.43%, and 442.86% higher than that of the control example, respectively), and the rate of change of magnetic permeability is stable between 0.83% and 1.04%, which is close to the control example and remains within a reasonable range, indicating that while improving the mechanical properties, the electromagnetic properties are not negatively affected, thereby improving the performance and stability of the electronic equipment.

[0022] 3. Significant Industry-Driven Impact: This process provides a new curing strategy and technical solution for the magnetic powder core processing industry, with promising application prospects and promotional value. It is not only applicable to the production of various existing magnetic powder cores, but also provides technical support for the research, development, and application of new magnetic powder core materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The photographs of the impregnated magnetic powder cores obtained in Comparative Example 1 and Example 1 after curing are shown;

[0024] Figure 2 The photographs of the impregnated magnetic powder cores obtained in Comparative Example 2 and Example 2 after curing are shown;

[0025] Figure 3 These are photos of the impregnated magnetic powder cores obtained in Comparative Example 3 and Example 3 after curing. DETAILED DESCRIPTION

[0026] To make the objectives, technical solutions, and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and examples. However, the accompanying drawings and examples do not limit the present invention. The present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0027] Example 1

[0028] In this embodiment, the formed magnetic powder core is impregnated and cured according to the following steps:

[0029] 1. Preparation of the impregnation solution: Based on the total weight of the impregnation solution, the types and amounts of the raw materials in the impregnation solution are shown in Table 1: Epoxy Resin E-51 (45wt%), Methyltetrahydrophthalic Anhydride (10wt%), 2,2-Dimethoxy-2-phenylacetophenone (2wt%), Tetrachloroethylene (40wt%), γ-Aminopropyltriethoxysilane (1.5wt%), and 1,4-Butanediol Diglycidyl Ether (1.5wt%). Mix and stir the raw materials to ensure uniform dispersion and stable performance.

[0030] 2. Impregnation treatment of magnetic powder core: Select a magnetic powder core with a length of 48.46mm, a width of 42.33mm, and a height of 11.02mm. Immerse it completely in the prepared impregnation solution for 30 minutes to allow the impregnation solution to fully penetrate the pores of the magnetic powder core. After impregnation, remove the magnetic powder core and clean it with an appropriate cleaning agent (the cleaning agent is the same solvent as the impregnation solution) for 6 minutes to remove excess impregnation solution from the surface of the magnetic powder core. After cleaning, place the magnetic powder core in a well-ventilated environment to air dry for 20 minutes to fully evaporate the solvent on the surface and prepare for subsequent curing.

[0031] 3. UV curing stage: Place the air-dried magnetic powder core under UV lamp for curing. Use UV lamp with wavelength of 365nm and UV intensity of 20mW / cm 2 During the UV irradiation process, the photosensitizer in the impregnation liquid quickly absorbs photon energy, triggering the resin polymerization reaction and initially forming a solidified structure, effectively locking the impregnation liquid and preventing it from flowing and seeping out.

[0032] 4. Heating and curing stage: The UV-cured magnetic powder core is placed in an oven for step-by-step heating and curing. First, the oven temperature is raised to 90°C and maintained for 1 hour to allow the impregnation liquid to initially cure and further cross-link. Then, the temperature is increased to 150°C and maintained for another 1 hour to ensure that the impregnation liquid is completely cured, thereby improving the overall strength and stability of the magnetic powder core.

[0033] Example 2

[0034] In this embodiment, the formed magnetic powder core is impregnated and cured according to the following steps:

[0035] 1. Preparation of the impregnation solution: Based on the total weight of the impregnation solution, the types and amounts of the raw materials in the impregnation solution are shown in Table 1: 40wt% of phenolic resin F-51, 14wt% of methyltetrahydrophthalic anhydride curing agent, 3wt% of benzophenone photosensitizer, 40wt% of tetrachloroethylene solvent, 1.5wt% of isopropyl triisostearyl titanate, and 1.5wt% of 1,4-butanediol diglycidyl ether. Mix and stir the raw materials to ensure uniform dispersion and stable performance.

[0036] 2. Impregnation treatment of magnetic powder core: same as in Example 1.

[0037] 3. UV curing stage: same as Example 1.

[0038] 4. Heating and curing stage: same as in Example 1.

[0039] Example 3

[0040] In this embodiment, the formed magnetic powder core is impregnated and cured according to the following steps:

[0041] 1. Preparation of the impregnation solution: Based on the total weight of the impregnation solution, the types and amounts of the raw materials in the impregnation solution are shown in Table 1: Epoxy Resin E-44 (50wt%), Methyltetrahydrophthalic Anhydride (10wt%), Butyl Benzoin Ether (3wt%), Tetrachloroethylene (35wt%), γ-Aminopropyltriethoxysilane (1wt%), and 1,4-Butanediol Diglycidyl Ether (1wt%). Prepare a uniform impregnation solution by accurately weighing and thoroughly stirring.

[0042] 2. Impregnation treatment of magnetic powder core: same as in Example 1.

[0043] 3. UV curing stage: same as Example 1.

[0044] 4. Heating and curing stage: same as in Example 1.

[0045] Comparative Example 1

[0046] The formed magnetic powder core was impregnated and cured in the same manner as in Example 1, except that the UV curing stage was not performed.

[0047] Comparative Example 2

[0048] The formed magnetic powder core is impregnated and cured in the same manner as in Example 2, except that the UV curing stage is omitted.

[0049] Comparative Example 3

[0050] The formed magnetic powder core was impregnated and cured in the same manner as in Example 3, except that the UV curing stage was not performed.

[0051] The photos of the samples obtained in each embodiment and comparative example are as follows Figures 1 to 3 The mechanical and magnetic properties of the solidified magnetic powder cores obtained in the examples and comparative examples were tested, and the test results are shown in Table 2.

[0052] The test results show that after heating and curing, the comparative examples 1 to 3 all showed glue coming out, while the examples 1 to 3 did not show glue coming out. This shows that the traditional single high-temperature heating and curing process is difficult to avoid the glue coming out problem. The process of UV curing followed by heating and curing in the present invention successfully overcomes this problem and fundamentally solves the negative impact of glue coming out on the appearance and performance of the magnetic core. The breaking tensile force of the magnetic powder cores of the comparative examples and the examples before impregnation is 70N, indicating that the basic mechanical properties of the initial magnetic powder cores are consistent and the experiments are comparable. The breaking tensile force of the impregnated magnetic powder cores of comparative examples 1 to 3 after curing is 280N, 350N, and 295N, respectively, and the breaking tensile force of the impregnated magnetic powder cores of examples 1 to 3 after curing is 400N, 610N, and 380N, respectively. The breaking tensile force of the examples is significantly higher than that of the comparative examples, indicating that the curing process of the present invention significantly improves the mechanical properties of the magnetic powder cores. The relative magnetic permeabilities of the magnetic powder cores of the comparative examples and the examples before impregnation were both 70, the relative magnetic permeabilities of the impregnated magnetic powder cores of comparative examples 1 to 3 after curing were 70.69, 70.47, and 70.55, respectively, and the relative magnetic permeabilities of the impregnated magnetic powder cores of examples 1 to 3 after curing were 70.73, 70.58, and 70.63, respectively. The changes in the relative magnetic permeabilities of the comparative examples and the examples after curing were small, and the values ​​were similar. This shows that the curing process of the present invention has little effect on the electromagnetic properties of the magnetic powder core while improving the mechanical properties of the magnetic powder core, and the magnetic permeability remains stable, which will not interfere with the normal electromagnetic operation of the magnetic powder core in electronic equipment.

[0053] Table 1. Types and amounts of raw materials used in the impregnation solutions of the examples and comparative examples

[0054]

[0055]

[0056] Table 2. Properties of the magnetic powder cores of various embodiments and comparative examples before and after impregnation and curing

[0057] performance Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Glue discharge after heating and curing Glue Glue Glue No glue No glue No glue Breaking tensile strength before impregnation (N) 70 70 70 70 70 70 Breaking tensile strength after impregnation and curing (N) 280 350 295 400 610 380 Breaking force change rate (%) 300 400 321.43 471.43 771.43 442.86 Relative magnetic permeability before impregnation 70 70 70 70 70 70 Relative magnetic permeability after impregnation and curing 70.69 70.47 70.55 70.73 70.58 70.63 Magnetic permeability change rate (%) 0.99 0.67 0.79 1.04 0.83 0.90

[0058] By comparing the above embodiments and comparative examples, it can be clearly seen that the curing process of the present invention has significant advantages in solving the problem of glue coming out of magnetic powder cores and improving the performance of magnetic powder cores. It can effectively meet the high quality requirements of electronic equipment for magnetic powder cores and provide a practical and feasible innovative technical solution for the field of magnetic powder core processing.

[0059] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection defined by the claims.

Claims

1. A step-by-step curing process for an efficient anti-glue impregnated magnetic powder core, characterized by: The formed magnetic powder core is impregnated in an impregnation liquid containing a photosensitizer, and then UV-cured and then heated for curing.

2. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 1 is characterized in that: The raw materials in the impregnation liquid are composed of the following components by mass percentage: 40%-50% resin, 10%-14% curing agent, 2%-3% photosensitizer, 35%-40% solvent, 1%-2% coupling agent, and 1%-2% diluent.

3. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 2 is characterized in that: The resin is selected from one of epoxy resin, phenolic resin, unsaturated polyester resin and silicone resin; the curing agent is selected from at least one of amine curing agent and acid anhydride curing agent; the photosensitizer is selected from one of benzoin ether photosensitizer, benzophenone or its derivatives, α-hydroxy ketone photosensitizer and thioxanthone photosensitizer.

4. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 2 is characterized in that: The solvent is selected from at least one of ethylene glycol monomethyl ether, benzyl alcohol, tetrachloroethylene, and ethylene glycol diacetate.

5. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 2 is characterized in that: The coupling agent is selected from at least one of γ-aminopropyltriethoxysilane and isopropyl triisostearyl titanate.

6. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 2 is characterized in that: The diluent is selected from at least one of 1,4-butanediol diglycidyl ether and benzyl glycidyl ether.

7. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 1 is characterized in that: The time for impregnation of the formed magnetic powder core in the impregnation liquid is 30 to 60 minutes.

8. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 1 is characterized in that: The ultraviolet curing is to place the impregnated magnetic powder core treated in the impregnation liquid under ultraviolet light for irradiation, and the wavelength, intensity and irradiation time of the ultraviolet light used are selected according to the selected photosensitizer.

9. The step-by-step curing process for the high-efficiency anti-glue impregnated magnetic powder core according to claim 1 is characterized in that: The heat curing is firstly curing at 80-150° C. for 1-3 hours, and then heating to 160-230° C. for curing for 1-3 hours.

10. A post-cured impregnated magnetic powder core obtained by the step-curing process according to any one of claims 1 to 9.

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