A high-temperature-resistant silicon steel sheet paint with a magnetic reinforcing function and a preparation method and application thereof

Abstract

The application discloses a high-temperature-resistant silicon steel sheet paint with a magnetic reinforcing function and a preparation method and application thereof, and belongs to the technical field of insulating paint and preparation thereof. The silicon steel sheet paint is prepared by compounding phenolic vinyl resin and high-heat-resistant epoxy resin as a base resin and by doping small-size magnetic core-grade ferrite as a silicon steel sheet paint modification filler. The silicon steel sheet paint has the magnetic reinforcing and high-temperature-resistant properties, and realizes the enhancement of the magnetic induction intensity of a motor core and the improvement of the high-temperature insulation performance.

Description

Technical Field

[0001] This invention relates to a high-temperature resistant silicon steel sheet paint with magnetic reinforcement function, its preparation method and application, belonging to the technical field of insulating coatings and their preparation. Background Technology

[0002] Silicon steel sheet varnish, a key insulating material for motor core laminations, is primarily coated onto the surface of silicon steel sheets. By blocking the electrical continuity between the sheets, it cuts off the path of induced eddy currents induced by alternating magnetic fields, effectively reducing core losses and ensuring motor operational safety. Silicon steel sheet insulating coatings are typically required to possess excellent electrical insulation strength, long-term heat resistance, machinability, and dimensional stability or self-adhesive strength under thermal cycling to maintain the integrity of the core structure and its electromagnetic properties. However, with the development of high-performance motors, especially aerospace micro-motors, towards high power density, miniaturization, and high-temperature service, more stringent comprehensive performance requirements have been placed on silicon steel sheet insulating coatings. On the one hand, limited by the design requirements of motor miniaturization and high power density, existing coatings, although non-magnetic materials, occupy limited magnetic circuit space, objectively increasing the air gap in the magnetic circuit and restricting further reduction in motor size. On the other hand, the temperature resistance of conventional silicon steel sheet coating systems is usually limited to 180℃ (H-class), which is difficult to withstand the instantaneous high temperature shock of nearly 300℃ in the aerospace environment, and is very likely to cause thermal decomposition, carbonization, and catastrophic failure of interlayer insulation performance. Therefore, it is essential to provide a new type of silicon steel sheet coating that can overcome the limitations of the non-magnetic properties of traditional coatings and has both ultra-high instantaneous temperature resistance and excellent insulation performance. Summary of the Invention

[0003] In order to solve the above-mentioned problems of existing silicon steel sheet coatings, the present invention provides a high-temperature resistant silicon steel sheet coating with magnetic reinforcement function, its preparation method and application.

[0004] The technical solution of this invention: One of the objectives of this invention is to provide a high-temperature resistant silicon steel sheet paint with magnetic reinforcement function, specifically comprising a base paint liquid, magnetic powder, ultraviolet initiator, leveling agent, and defoamer; The magnetic powder is PC40 or PC95, and the mass ratio of magnetic powder to base paint is (1.2-1.35):1.

[0005] Further specified, the magnetic powder particle size is 1250 mesh.

[0006] Further specifying, the base paint liquid includes phenolic vinyl resin, styrene, heat-resistant epoxy resin, and latent curing agent of epoxy resin in a mass ratio of 1:(1.05-1.10):(0.85-0.87):(0.085-0.11).

[0007] Furthermore, the latent curing agent for epoxy resin is 4,4'-diphenyl sulfone diamine.

[0008] Further specified, the UV initiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the amount of UV initiator is 4-5% of the mass of the base paint.

[0009] Further specifying, the leveling agent is BYK371, and the leveling agent accounts for 1% of the mass of the base paint.

[0010] Further specified, the defoamer is Dow DF-103, and the amount of defoamer used is 0.5% of the mass of the base paint.

[0011] The second objective of this invention is to provide a method for preparing the above-mentioned high-temperature resistant silicon steel sheet paint with magnetic reinforcement function, the method comprising the following steps: (1) Phenolic vinyl resin, styrene, heat-resistant epoxy resin, and latent curing agent of epoxy resin are mixed evenly at room temperature to obtain the base paint liquid; (2) Add magnetic powder to the base paint liquid, use a planetary ball mill to perform the first dispersion treatment under the action of zirconia spherical grinding beads, and finally add UV initiator, leveling agent and defoamer for the second dispersion treatment to obtain silicon steel sheet paint.

[0012] Further, the first dispersion treatment was set at a rotation speed of 4000 rad / min for 5 hours.

[0013] Further specified, the second dispersion treatment speed is 500 rad / min, and the time is 0.5 h.

[0014] The third objective of this invention is to provide a method for using the above-mentioned high-temperature resistant silicon steel sheet paint with magnetic reinforcement function. Specifically, the high-temperature resistant silicon steel sheet paint with magnetic reinforcement function is sprayed onto the surface of the silicon steel sheet, cured by ultraviolet light irradiation, and finally subjected to stamping, stacking and pressure curing treatment to obtain the motor core.

[0015] Further specified, the ultraviolet light wavelength is 365-370nm.

[0016] Beneficial effects: This invention constructs a solvent-free UV-curing system through the synergistic compounding of phenolic vinyl resin and high-heat-resistant epoxy resin. This fundamentally solves the environmental bottleneck caused by the evaporation of organic solvents in traditional silicon steel sheet coatings, while significantly improving production efficiency and the upper limit of the heat resistance of the cured product, enabling it to withstand instantaneous high-temperature conditions of nearly 300°C. Furthermore, by introducing small-sized magnetic core-grade ferrite as a functional filler, it breaks the traditional perception that insulating coatings are non-magnetic. On the one hand, the soft magnetic properties of ferrite endow the insulating layer with a certain degree of magnetic permeability, effectively reducing the magnetic circuit gap of the non-magnetic coating, thereby improving the overall magnetic induction intensity of the core and achieving magnetic reinforcement of the insulating coating. On the other hand, the rigid support of ferrite particles maintains the interlayer physical spacing and structural stability even when the organic phase softens at high temperatures. Combined with the secondary hot-pressing self-adhesive properties provided by the latent curing agent of the high-heat-resistant epoxy resin, it ensures the dimensional accuracy and structural rigidity of the motor core under extreme thermal cycling, while simultaneously enhancing the magnetic induction intensity of the motor core and improving its high-temperature insulation performance. Attached Figure Description

[0017] Figure 1 Comparison of saturation magnetic flux density of paint film on silicon steel sheets with different amounts of magnetic powder; Figure 2 A comparison chart showing the film hardness of silicon steel sheet coatings with different ratios of phenolic vinyl resin to epoxy resin. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0019] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials, reagents, methods, and instruments used are all conventional materials, reagents, methods, and instruments in the art, and can be obtained commercially by those skilled in the art.

[0020] The phenolic vinyl resin used in the following examples is Lilians 950z; the heat-resistant epoxy resin is AG80, manufactured by Shanghai Huayi Resin Co., Ltd.; the magnetic powder is PC40 magnetic powder or PC95 magnetic powder, manufactured by Tokyo Electric Chemical Industry Co., Ltd. (TDK).

[0021] Example 1 This embodiment of the preparation of high-temperature resistant silicon steel sheet coating with magnetic reinforcement function includes the following steps: (1) Preparation of base paint: Phenolic vinyl resin, styrene, heat-resistant epoxy resin and epoxy resin latent curing agent DDS are mixed uniformly at room temperature in a mass ratio of 1:1.10:0.87:0.085 to obtain base paint.

[0022] (2) Preparation of silicon steel sheet paint: 1250 mesh PC95 magnetic powder and base paint liquid were added to a planetary ball mill at a mass ratio of 1.2:1. Under the action of zirconia spherical grinding beads, the mixture was dispersed at 4000 rad / min for 5 hours and mixed evenly. Finally, 1% leveling agent BYK371, 0.5% defoamer DF-103 and 2.5% UV initiator TPCO were added to the base paint liquid. The mixture was then dispersed at 500 rad / min for 0.5 hours to obtain high temperature resistant silicon steel sheet paint with magnetic reinforcement function.

[0023] The method of using the high-temperature resistant silicon steel sheet paint with magnetic reinforcement function prepared in this embodiment is as follows: the silicon steel sheet paint is uniformly sprayed onto the surface of the silicon steel sheet with a thickness of 15μm, and then irradiated with an LED ultraviolet lamp with a wavelength of 365-370nm and a power of 1000W for 15s to completely cure the phenolic vinyl resin. Finally, after stamping, stacking and pressing, it is cured at 150℃ for 2h to obtain the motor core.

[0024] Example 2 The difference between this embodiment and embodiment 1 is that in step (2), the mass ratios of 1250-mesh PC40 magnetic powder and base paint are 1.10:1, 1.15:1, 1.25:1, 1.30:1, 1.35:1, 1.40:1, 1.45:1, 1.50:1 and 1.60:1, respectively, and 1250-mesh PC40 magnetic powder is used to replace the PC40 magnetic powder in embodiment 1. The remaining process steps and parameter settings are the same as in embodiment 1.

[0025] The saturation magnetic flux density of the silicon steel sheet coatings prepared in Examples 1 and 2 was characterized. Specifically, the silicon steel sheet coating was uniformly sprayed onto the surface of the silicon steel sheet to a thickness of 15 μm, and then irradiated with a 1000W LED ultraviolet lamp with a wavelength of 365-370 nm for 15 seconds to allow the phenolic vinyl resin to fully cure, thus obtaining the coating film. The test results are as follows. Figure 1 As shown, when the mass ratio of magnetic powder to base paint exceeds 1.35:1, the excessive amount of magnetic powder leads to excessively high paint viscosity, making it impossible to form. Figure 1It is known that as the amount of magnetic powder added gradually increases, the saturation magnetic flux density of the paint film also increases. However, if the amount is too large, it will lead to excessively high viscosity of the paint, making it difficult to apply. Therefore, a mass ratio of magnetic powder to base paint of 1.35:1 (denoted as 135wt% in the figure) is selected as the maximum upper limit. At the same time, when the mass ratio of magnetic powder to base paint is lower than 1.20:1 (denoted as 120wt% in the figure), the magnetic reinforcement provided by PC40 powder is limited. Taking into account other properties, this content is selected as the minimum amount of magnetic powder.

[0026] Example 3 The difference between this embodiment and embodiment 1 is that the mass ratio of phenolic vinyl resin to epoxy resin in step (1) is 1:0.7, 1:0.8, 1:0.83, 1:0.85, 1:0.9 and 1:1, respectively. The remaining process steps and parameter settings are the same as in embodiment 1.

[0027] The hardness of the coating films of the silicon steel sheets prepared in Examples 1 and 3 was characterized. Specifically, the silicon steel sheet coating was uniformly sprayed onto the surface of the silicon steel sheet to a thickness of 15 μm, and then irradiated with an LED ultraviolet lamp with a wavelength of 365-370 nm and a power of 1000 W for 15 seconds to allow the phenolic vinyl resin to fully cure, thus obtaining the coating film. The test results are as follows. Figure 2 As shown in the figure, the function of phenolic vinyl resin is to form surface drying and provide initial film hardness, while the function of epoxy resin is to provide subsequent bonding. Therefore, when the proportion of phenolic vinyl resin is high, the film hardness is high, but the bonding strength is poor; when its proportion is low, the film hardness is low, but the bonding strength is high. To obtain a parallel performance range, the selected resin matrix ratio is 1:(0.85-0.87) by mass of phenolic vinyl resin and heat-resistant epoxy resin.

[0028] Example 4 The difference between this embodiment and Embodiment 1 is as follows: in step (1), phenolic vinyl resin, styrene, heat-resistant epoxy resin, and latent curing agent DDS of epoxy resin are uniformly mixed at room temperature in a mass ratio of 1:1.05:0.85:0.11; in step (2), 1250-mesh PC40 magnetic powder and base paint are mixed in a mass ratio of 1.35:1; in step (3), the curing temperature is 130℃ and the time is 4h; the remaining process steps and parameter settings are the same as in Embodiment 1.

[0029] The properties of the coating films of silicon steel sheets prepared in Examples 1 and 4 were characterized. Specifically, the silicon steel sheet coating was uniformly sprayed onto the surface of the silicon steel sheet to a thickness of 15 μm, and then irradiated with an LED ultraviolet lamp with a wavelength of 365-370 nm and a power of 1000 W for 15 s to allow the phenolic vinyl resin to fully cure, thus obtaining the coating film. The test results are shown in Table 1 below.

[0030] Table 1 Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make various modifications and alterations without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be determined by the claims.

Claims

1. A high-temperature resistant silicon steel sheet coating with magnetic reinforcement function, characterized in that, Includes base paint, magnetic powder, UV initiator, leveling agent, and defoamer; The magnetic powder is PC40 or PC95, and the mass ratio of magnetic powder to base paint is (1.2-1.35):

1.

2. The high-temperature resistant silicon steel sheet paint with magnetic reinforcement function according to claim 1, characterized in that, The base paint consists of phenolic vinyl resin, styrene, heat-resistant epoxy resin, and latent curing agent of epoxy resin in a mass ratio of 1:(1.05-1.10):(0.85-0.87):(0.085-0.11).

3. The high-temperature resistant silicon steel sheet coating with magnetic reinforcement function according to claim 2, characterized in that, The latent curing agent for epoxy resin is 4,4'-diphenyl sulfone diamine.

4. The high-temperature resistant silicon steel sheet paint with magnetic reinforcement function according to claim 1, characterized in that, The UV initiator is 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, and the amount of UV initiator used is 4-5% of the mass of the base paint.

5. The high-temperature resistant silicon steel sheet coating with magnetic reinforcement function according to claim 1, characterized in that, The leveling agent is BYK371, and the leveling agent accounts for 1% of the mass of the base paint.

6. The high-temperature resistant silicon steel sheet coating with magnetic reinforcement function according to claim 1, characterized in that, The defoamer is Dow DF-103, and the amount of defoamer used is 0.5% of the mass of the base paint.

7. A method for preparing a high-temperature resistant silicon steel sheet paint with magnetic reinforcement function as described in any one of claims 1 to 6, characterized in that, include: (1) Phenolic vinyl resin, styrene, heat-resistant epoxy resin, and latent curing agent of epoxy resin are mixed evenly at room temperature to obtain the base paint liquid; (2) Add magnetic powder to the base paint liquid, use a planetary ball mill to perform the first dispersion treatment under the action of zirconia spherical grinding beads, and finally add UV initiator, leveling agent and defoamer for the second dispersion treatment to obtain silicon steel sheet paint.

8. The method for preparing high-temperature resistant silicon steel sheet paint with magnetic reinforcement function according to claim 7, characterized in that, The first dispersion treatment was carried out at a rotation speed of 4000 rad / min for 5 hours.

9. The method for preparing high-temperature resistant silicon steel sheet paint with magnetic reinforcement function according to claim 7, characterized in that, The second dispersion treatment was carried out at a rotation speed of 500 rad / min for 0.5 h.

10. A method of using the high-temperature resistant silicon steel sheet paint with magnetic reinforcement function as described in any one of claims 1 to 6, characterized in that, High-temperature resistant silicon steel sheet paint with magnetic reinforcement function is sprayed onto the surface of silicon steel sheet, cured by ultraviolet light, and finally processed by stamping, stacking and pressure curing to obtain motor core.

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