Novel micro-nano porous bus insulating film and preparation method thereof

Abstract

The invention relates to a novel micro-nano porous bus insulating film and a preparation method thereof, and belongs to the field of insulating films. The reinforcing layer is arranged on the lower surface of the base body layer; the wear-resistant assembly is arranged on the upper surface of the base body layer and comprises a wear-resistant layer which is arranged on the upper surface of the base body layer; and the plurality of graphite columns are uniformly distributed on the upper surface of the wear-resistant layer. According to the novel micro-nano porous bus insulating film and the preparation method thereof, through a unique matrix layer preparation technology, construction of micron-level main holes and nano-level secondary holes is achieved, the heat conduction performance and the insulating performance of the insulating film are effectively improved, the enhancement layer adopts the silane coupling agent layer, chemical bonding can be formed between the enhancement layer and the bus metal surface and the matrix layer, and the heat conduction performance and the insulating performance of the insulating film are improved. The adhesive force between the insulating film and the bus is obviously enhanced, and the stability of the whole structure is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of insulating films, and specifically to a novel micro-nano porous busbar insulating film and a preparation method thereof. Background Art

[0002] An insulating film, as the name implies, is a thin film material with insulating properties. It is usually made of dielectric materials, which are used in electronics and electrical engineering to prevent current from passing through or reduce current leakage.

[0003] In practical applications, existing insulating films often face a serious problem, that is, the abrasion damage caused by the friction between external objects and the film body. This kind of damage not only reduces the protection performance of the film body, but may also seriously affect the insulation performance of the equipment. When the insulating film is scratched, scratches, cracks or even perforations may appear on its surface. These damages will weaken the physical strength and electrical insulation ability of the film body. Therefore, this application proposes a novel micro-nano porous busbar insulating film and a preparation method thereof to solve the above contact problem. Summary of the Invention

[0004] Aiming at the deficiencies of the prior art, the present invention provides a novel micro-nano porous busbar insulating film and a preparation method thereof, which have the advantages of improving the wear resistance of the insulating film, etc., and solve the problem that the insulating film is easily damaged when scratched.

[0005] To achieve the above object, the present invention provides the following technical solution: A novel micro-nano porous busbar insulating film, comprising a substrate layer;

[0006] A reinforcing layer, provided on the lower surface of the substrate layer;

[0007] A wear-resistant component provided on the upper surface of the substrate layer, which includes a wear-resistant layer provided on the upper surface of the substrate layer; a plurality of graphite columns, evenly distributed on the upper surface of the wear-resistant layer.

[0008] Further, the substrate layer is made by mixing a BNNS dispersion liquid and a polyimide solution;

[0009] The BNNS dispersion liquid is made by dissolving boron nitride nanosheets and sodium carboxymethyl cellulose in deionized water.

[0010] Further, the substrate layer has a plurality of micron-sized main pores, and the pore diameter of the micron-sized main pores is 5-50 μm.

[0011] Further, the inner side of the micron-sized main pores has a plurality of nano-sized secondary pores, and the diameter of the nano-sized secondary pores is 20-50 nm.

[0012] Further, the reinforcing layer is a silane coupling agent layer.

[0013] Further, the friction-resistant component further includes a number of card slots, which are evenly distributed on the upper surface of the wear-resistant layer, and a number of graphite columns are respectively arranged inside the number of card slots.

[0014] Further, the distance from the inner bottom surface of the card slot to the upper surface of the wear-resistant layer is greater than the radius of the graphite column.

[0015] Further, the wear-resistant layer is a silicon nitride layer.

[0016] Further, the card slots are formed on the wear-resistant layer by photolithography and etching processes.

[0017] The preparation method of the above-mentioned novel micro-nano porous busbar insulating film includes the following technological steps:

[0018] S1 Dissolve boron nitride nanosheets and sodium carboxymethylcellulose in deionized water according to a certain ratio, ultrasonically disperse for 30 minutes at a power of 40 kHz and 300 W, and then magnetically stir at a speed of 500-800 rpm for 2 hours to obtain a stable BNNS dispersion, ensuring that the absolute value of its ζ potential > 30 mV to achieve the monodispersion of boron nitride nanosheets;

[0019] S2 Mix the prepared BNNS dispersion with a polyimide solution (solid content 15-20%), and through high-shear stirring (3000-5000 rpm), make BNNS evenly dispersed in the polyimide solution to form a uniform composite solution;

[0020] S3 Inject the composite solution into a mold, set a temperature gradient of -80°C at the top and -20°C at the bottom in an environment of -80°C, and perform two-way freezing at a freezing rate of 0.5-2°C / min to make the ice crystals in the solution grow along the temperature gradient direction to form an oriented ice crystal template. Then, perform freeze-drying for 48 hours under a vacuum of <10 Pa, and the ice crystals directly sublimate to form micron-sized main pores with a pore diameter of 5-50 μm. Perform hot pressing treatment on the freeze-dried sample at 180°C and 5 MPa, and introduce supercritical CO2 of 10-15 MPa at the same time. During the hot pressing process, CO2 diffuses into the sample, and after depressurization, nano-sized secondary pores with a diameter of 20-50 nm are formed inside the micron-sized main pores. Thus, the preparation of the matrix layer is completed;

[0021] S4 Coating the lower surface of the matrix layer with silane coupling agent KH550 by the scraping method and curing at 80°C for 2 hours to form the reinforcement layer 2;

[0022] S5 Deposit silicon nitride on the upper surface of the matrix layer by CVD method, with a deposition temperature of 800°C, a pressure of 10 Pa, a gas flow rate of SiH4 50 sccm and NH3 100 sccm, and a deposition time of 2 hours to form a wear-resistant layer;

[0023] On the wear-resistant layer, a card slot with a diameter of 100 μm and a depth of 50 μm is formed through photolithography and etching processes. A graphite column with a diameter of 98 μm and a height of 50 μm is processed from graphite and embedded in the card slot.

[0024] Compared with the prior art, the technical solution of the present application has the following beneficial effects:

[0025] The novel micro-nano porous busbar insulating film and its preparation method realize the construction of micron-level main pores and nano-level secondary pores through a unique matrix layer preparation process, effectively improving the thermal conductivity and insulation performance of the insulating film. The reinforcing layer adopts a silane coupling agent layer, which can form chemical bonding with the surface of the busbar metal and the matrix layer, significantly enhancing the adhesion between the insulating film and the busbar and improving the stability of the overall structure. In the friction-resistant component, the silicon nitride wear-resistant layer has excellent hardness and wear resistance, and the setting of the graphite column further reduces the friction coefficient, effectively reducing the wear of the insulating film during use and extending the service life of the insulating film, meeting the application requirements of the busbar in complex environments. Description of the Drawings

[0026] Figure 1 It is a partial exploded three-dimensional structural schematic diagram in the preferred embodiment of the present invention;

[0027] Figure 2 It is a partial three-dimensional structural schematic diagram in the preferred embodiment of the present invention;

[0028] Figure 3 It is a partial exploded three-dimensional structural schematic diagram of the friction-resistant component in the preferred embodiment of the present invention;

[0029] Figure 4 It is the preferred embodiment of the present invention Figure 3 The enlarged three-dimensional structural schematic diagram at position A in the middle.

[0030] In the figure: 1, matrix layer; 2, reinforcing layer; 3, friction-resistant component; 31, wear-resistant layer; 32, card slot; 33, graphite column. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0032] Please refer to Figures 1-4 , a novel micro-nano porous busbar insulating film in this embodiment, matrix layer 1;

[0033] Reinforcing layer 2, provided on the lower surface of the matrix layer 1;

[0034] The wear-resistant component 3 disposed on the upper surface of the substrate layer 1 includes a wear-resistant layer 31 disposed on the upper surface of the substrate layer 1; a plurality of graphite columns 33 evenly distributed on the upper surface of the wear-resistant layer 31.

[0035] In this embodiment, a novel micro-nano porous busbar insulating film is provided. Through the substrate layer 1, it can be used to provide electrical insulation in electrical equipment and electronic components. And under the action of the reinforcing layer 2, it can form a chemical bond with the busbar metal surface and the substrate layer, significantly enhancing the adhesion of the insulating film to the busbar and improving the stability of the overall structure. At the same time, under the action of the wear-resistant component 3, the wear-resistant effect of the substrate layer 1 can be improved, so that when the substrate layer 1 is scratched, it will not easily produce scratches, cracks or even perforations, thereby improving the physical strength and electrical insulation ability of the substrate layer 1.

[0036] Furthermore, the substrate layer 1 is made by mixing BNNS dispersion liquid and polyimide solution;

[0037] The BNNS dispersion liquid is made by dissolving boron nitride nanosheets and sodium carboxymethyl cellulose in deionized water.

[0038] More specifically, the substrate layer 1 has a plurality of micron-sized main pores, and the pore diameter of the micron-sized main pores is 5 - 50 μm;

[0039] The inner side of the micron-sized main pores has a plurality of nano-sized secondary pores, and the diameter of the nano-sized secondary pores is 20 - 50 nm. In this way, under the action of the micron-sized main pores, a continuous heat conduction channel can be formed in the substrate layer 1, so that the heat generated during the operation of the equipment busbar can be better dissipated. And under the action of the nano-sized secondary pores, the dielectric constant can be reduced (close to 1 of air), suppressing partial discharge and corona phenomena, thereby improving the insulation strength of the substrate layer 1.

[0040] Furthermore, the reinforcing layer 2 is a silane coupling agent layer.

[0041] Further, as Figures 3-4 shown, the wear-resistant component 3 in the preferred embodiment of the present invention further includes a plurality of card slots 32 evenly distributed on the upper surface of the wear-resistant layer 31, and a plurality of graphite columns 33 are respectively disposed inside the plurality of card slots 32.

[0042] Furthermore, the wear-resistant layer 31 is a silicon nitride layer; the distance from the inner bottom surface of the card slot 32 to the upper surface of the wear-resistant layer 31 is greater than the radius of the graphite column 33.

[0043] In this embodiment, multiple preferred embodiments of the friction-resistant component 3 are given. By using silicon nitride as the wear-resistant layer 31, it itself has high hardness (Mohs hardness up to 9-9.5), low friction coefficient and excellent chemical stability. During the operation of the busbar, the external frictional force first acts on the wear-resistant layer 31. Thanks to its hard crystal structure, silicon nitride can effectively resist wear. At the same time, the card slots 32 uniformly distributed on the wear-resistant layer 31 and the graphite columns 33 form a synergistic effect. The graphite columns 33 have good lubrication performance, and their layered crystal structure makes it easy for slip to occur between layers. When the surface of the insulating film is rubbed, the graphite columns 33 can undergo a certain degree of fretting within the card slots 32, converting the sliding friction into the relative slip between the graphite layers, further reducing the frictional resistance and reducing the direct wear between the wear-resistant layer 31 and the external friction objects.

[0044] The preparation method of the above-mentioned novel micro-nano porous busbar insulating film includes the following technological steps:

[0045] S1 Dissolve boron nitride nanosheets and sodium carboxymethyl cellulose in deionized water according to a certain ratio, ultrasonically disperse them at a power of 40 kHz and 300 W for 30 minutes, and then magnetically stir them at a speed of 500-800 rpm for 2 hours to obtain a stable BNNS dispersion, ensuring that the absolute value of its ζ potential > 30 mV to achieve the monodispersion of boron nitride nanosheets;

[0046] S2 Mix the above-prepared BNNS dispersion with a polyimide solution (solid content 15-20%) and, through high-shear stirring (3000-5000 rpm), make the BNNS uniformly dispersed in the polyimide solution to form a uniform composite solution;

[0047] S3 Inject the composite solution into a mold. Under an environment of -80°C, set a temperature gradient of -80°C at the top and -20°C at the bottom, and perform two-way freezing at a freezing rate of 0.5-2°C / min to make the ice crystals in the solution grow along the temperature gradient direction to form an oriented ice crystal template. Then, perform freeze-drying for 48 hours under a vacuum of <10 Pa, and the ice crystals directly sublime to form micron-sized main pores with a pore diameter of 5-50 μm. Perform hot pressing treatment on the freeze-dried sample at 180°C and 5 MPa, and introduce supercritical CO2 of 10-15 MPa at the same time. During the hot pressing process, CO2 diffuses into the sample, and after depressurization, nano-sized secondary pores with a diameter of 20-50 nm are formed inside the micron-sized main pores, thus completing the preparation of the matrix layer 1;

[0048] S4 Coating the lower surface of the matrix layer 1 with a silane coupling agent KH550 by the scraping method and curing it at 80°C for 2 hours to form the reinforcing layer 2;

[0049] The S5 uses the CVD method to deposit silicon nitride on the upper surface of the substrate layer 1. The deposition temperature is 800 °C, the pressure is 10 Pa, the gas flow rates are 50 sccm of SiH4 and 100 sccm of NH3, and the deposition time is 2 hours to form the wear-resistant layer 31;

[0050] On the wear-resistant layer 31, a card slot 32 with a diameter of 100 μm and a depth of 50 μm is opened through photolithography and etching processes. The graphite is processed into a graphite column 33 with a diameter of 98 μm and a height of 50 μm and is embedded in the card slot 32.

[0051] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the term "comprising", "including" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent in such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the existence of additional identical elements in the process, method, article or device comprising the element.

[0052] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill 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 present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A novel micro-nano porous busbar insulating film, characterized in that, It includes a substrate layer (1); a reinforcing layer (2) provided on the lower surface of the substrate layer (1); a wear-resistant component (3) provided on the upper surface of the substrate layer (1), which includes a wear-resistant layer (31) provided on the upper surface of the substrate layer (1); a number of graphite columns (33) evenly distributed on the upper surface of the wear-resistant layer (31).

2. The novel micro-nano porous busbar insulating film according to claim 1, characterized in that: The substrate layer (1) is made by mixing BNNS dispersion liquid and polyimide solution; The BNNS dispersion liquid is made by dissolving boron nitride nanosheets and sodium carboxymethyl cellulose in deionized water.

3. The novel micro-nano porous busbar insulating film according to claim 2, wherein: The substrate layer (1) has a number of micron-sized main pores, and the pore diameter of the micron-sized main pores is 5 - 50 μm.

4. A novel micro-nano porous busbar insulating film according to claim 3, characterized in that: There are a number of nano-sized secondary pores inside the micron-sized main pores, and the diameter of the nano-sized secondary pores is 20 - 50 nm.

5. A novel micro-nano porous busbar insulating film according to claim 1, characterized in that: The reinforcing layer (2) is a silane coupling agent layer.

6. A novel micro-nano porous busbar insulation film according to claim 1, characterized in that: The wear-resistant component (3) further includes a number of card slots (32) evenly distributed on the upper surface of the wear-resistant layer (31), and a number of graphite columns (33) are respectively provided inside the number of card slots (32).

7. A novel micro-nano porous busbar insulating film according to claim 6, characterized in that: The distance from the inner bottom surface of the card slot (32) to the upper surface of the wear-resistant layer (31) is greater than the radius of the graphite column (33).

8. A novel micro-nano porous busbar insulating film according to claim 7, characterized in that: The wear-resistant layer (31) is a silicon nitride layer.

9. A novel micro-nano porous busbar insulating film according to claim 8, characterized in that: The card slots (32) are formed on the wear-resistant layer (31) through photolithography and etching processes.

10. A method for preparing a novel micro-nano porous busbar insulating film according to any one of claims 1 to 9, characterized in that: It includes the following steps: S1 Dissolve boron nitride nanosheets and sodium carboxymethyl cellulose in deionized water according to a certain ratio, ultrasonically disperse for 30 minutes at a power of 40 kHz and 300 W, and then magnetically stir at a rotation speed of 500 - 800 rpm for 2 hours to obtain a stable BNNS dispersion liquid, ensuring that the absolute value of its ζ potential > 30 mV to achieve the monodispersion of boron nitride nanosheets; S2 Mix the above-prepared BNNS dispersion liquid with a polyimide solution (solid content 15 - 20%) and, through high-shear stirring (3000 - 5000 rpm), make BNNS evenly dispersed in the polyimide solution to form a uniform composite solution; S3 Inject the composite solution into a mold, in an environment of -80°C, set a temperature gradient of -80°C at the top and -20°C at the bottom, and perform two-way freezing at a freezing rate of 0.5 - 2°C / min to make the ice crystals in the solution grow along the temperature gradient direction to form an oriented ice crystal template. Then, perform freeze-drying for 48 hours under a vacuum of < 10 Pa, and the ice crystals directly sublimate to form micron-sized main pores with a pore diameter of 5 - 50 μm. Perform hot pressing treatment on the freeze-dried sample at 180°C and 5 MPa, and simultaneously introduce supercritical CO2 of 10 - 15 MPa. During the hot pressing process, CO2 diffuses into the sample, and after depressurization, nano-sized secondary pores with a diameter of 20 - 50 nm are formed inside the micron-sized main pores. Thus, the preparation of the substrate layer (1) is completed; S4 Coating the lower surface of the substrate layer (1) with silane coupling agent KH550 by the scraping method and curing at 80°C for 2 hours to form the reinforcing layer (2); S5 uses the CVD method to deposit silicon nitride on the upper surface of the substrate layer (1) at a deposition temperature of 800 °C, a pressure of 10 Pa, a gas flow rate of 50 sccm of SiH4 and 100 sccm of NH3, and a deposition time of 2 hours to form a wear-resistant layer (31); On the wear-resistant layer (31), a card slot (32) with a diameter of 100 μm and a depth of 50 μm is opened through photolithography and etching processes. A graphite column (33) with a diameter of 98 μm and a height of 50 μm is machined from graphite and embedded in the card slot (32).

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