Rigid-soft combined non-woven fabric grinding pad and preparation method thereof

Abstract

The invention relates to the field of grinding pads, and particularly discloses a rigid-flexible combined non-woven fabric grinding pad and a preparation method thereof. The invention discloses a rigid-flexible combined non-woven fabric grinding pad and a preparation method thereof. The rigid-flexible combined non-woven fabric grinding pad comprises the following raw materials in parts by weight: 50-60 parts of a non-woven fabric base material, 8-12 parts of a grinding material and 20-25 parts of adhesive resin, the non-woven fabric base material comprises the following raw materials: polyamide fibers, polyester fibers and modified carbon fibers; in addition, the preparation method has the advantage of improving the wear resistance and heat resistance of the grinding pad.

Description

Technical Field

[0001] The present application relates to the field of polishing pads, and more specifically, to a rigid-flexible nonwoven polishing pad and a preparation method thereof. Background Art

[0002] Abrasive pads are a type of abrasive material that is widely used in the fields of metal surface treatment and coating removal. Traditional abrasive materials are mostly made of natural fibers or synthetic fibers. Currently, the common abrasive materials on the market mainly include natural fiber abrasive pads, synthetic fiber abrasive pads, and non-woven fabric abrasive pads. Natural fibers have lower costs, but lower strength and poor wear resistance, while synthetic fiber abrasive pads have higher strength but poor heat resistance, and the high temperature generated during the grinding process can easily cause them to deform.

[0003] Existing non-woven polishing pads are usually made of a single type of fiber. Although their wear resistance and heat resistance are improved, they still have problems such as short service life, insufficient heat resistance and deformation when working intensity increases, which affects work efficiency. They still cannot meet the requirements in terms of wear resistance and heat resistance. Summary of the invention

[0004] In order to improve the wear resistance and heat resistance of the polishing pad, the present application provides a rigid-flexible non-woven polishing pad and a preparation method thereof.

[0005] In the first aspect, the present application provides a rigid-flexible nonwoven polishing pad, which adopts the following technical solution: A rigid-flexible nonwoven fabric polishing pad comprises the following raw materials in parts by weight: 50-60 parts of a nonwoven fabric substrate, 8-12 parts of abrasives and 20-25 parts of an adhesive resin; The non-woven fabric substrate comprises the following raw materials: polyamide fiber, polyester fiber and modified carbon fiber.

[0006] By adopting the above technical scheme, polyamide fiber and polyester fiber have good elasticity and strength, and a non-woven fabric substrate with good wear resistance and elasticity can be produced. The adhesive resin is mixed with the abrasive and the non-woven fabric substrate is impregnated. The abrasive can be solidified on the non-woven fabric substrate, and the non-woven fabric substrate can be reinforced to improve its strength. Adding modified carbon fiber can further enhance the mechanical strength and wear resistance of the non-woven fabric substrate. At the same time, the modified carbon fiber has good thermal conductivity and can conduct and disperse the heat generated during the grinding process, thereby improving the heat resistance of the grinding pad.

[0007] Preferably, the mass ratio of the polyamide fiber, the polyester fiber and the modified carbon fiber is (1.05-1.36):(0.98-1.21):(0.23-0.34).

[0008] By adopting the above technical scheme, the non-woven fabric substrate made by mixing polyamide fiber, polyester fiber and modified carbon fiber has good elasticity and wear resistance. Controlling the mass ratio of the three can make the three play a synergistic role, so that the mechanical properties of the non-woven fabric substrate are excellent.

[0009] Preferably, the abrasive is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, iron oxide, chromium oxide, and diamond, and the average particle size of the abrasive is 5-200 nm.

[0010] Preferably, the preparation method of the modified carbon fiber comprises the following steps: adding multi-walled carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid, condensing and refluxing at 115-120°C for 1-1.2h, washing, filtering, and drying to obtain modified carbon nanotubes, dissolving polyacrylonitrile in N,N'-dimethylformamide to obtain a spinning solution, and ultrasonically dispersing the modified carbon nanotubes in the spinning solution, performing electrospinning to obtain modified polyacrylonitrile fibers, and performing pre-oxidation and carbonization to obtain modified carbon fibers.

[0011] By adopting the above technical scheme, after the multi-walled carbon nanotubes are treated with mixed acid, the surface of the multi-walled carbon nanotubes contains carboxyl groups, which improves the dispersibility of the modified carbon nanotubes in the spinning solution, so that the modified carbon nanotubes can form a hybrid structure with the carbon fibers, and the obtained modified carbon fibers have excellent mechanical properties.

[0012] Preferably, the added amount of the modified carbon nanotubes is 3-5 wt % of the polyacrylonitrile.

[0013] By adopting the above technical solution and controlling the addition amount of modified carbon nanotubes, continuous and uniform modified polyacrylonitrile fibers can be obtained by electrospinning, which is beneficial to the formation of modified carbon fibers.

[0014] Preferably, the adhesive resin comprises the following raw materials in parts by mass: epoxy resin, amine curing agent and modified silica aerogel in a mass ratio of (18.36-21.34):(14.32-15.26):(1.51-1.89).

[0015] By adopting the above technical scheme, the epoxy resin has relatively excellent wear resistance after curing, and the liquid epoxy resin has relatively suitable fluidity and viscosity, so that the abrasive can be evenly distributed throughout the non-woven fabric substrate with the epoxy resin. The addition of modified silica aerogel can increase the viscosity of the epoxy resin after curing and improve its durability.

[0016] Preferably, the preparation method of the modified silica aerogel comprises the following steps: adding hydrochloric acid and hexadecyltrimethylammonium bromide to water and mixing evenly, adding methyltriethoxysilane and dimethyldiethoxysilane, magnetically stirring at 20-25°C for 2-2.5h, adding silica microspheres and ultrasonically dispersing them evenly, adding urea, standing at 75-80°C to obtain a wet gel, washing, and drying to obtain the modified silica aerogel.

[0017] By adopting the above technical solution, silica microspheres can provide nuclei for silica aerogel, refine the size of silica aerogel secondary particles, transform its structure into a tightly stacked form, effectively improve its mechanical properties, and thus further improve the performance of the adhesive resin after curing.

[0018] Preferably, the added amount of the silica microspheres is 4.89-5.32 wt % of the total weight of the modified silica aerogel.

[0019] By adopting the above technical solution and controlling the addition amount of silica microspheres, the porosity of the modified silica aerogel can be moderate and the elasticity can be good. Too low an addition amount can easily make the structure of the modified silica aerogel loose, while too high an addition amount can easily make its porosity too low, thereby reducing its elasticity.

[0020] In a second aspect, the present application provides a method for preparing a rigid-flexible nonwoven polishing pad, using the following technical solution: A method for preparing a rigid-flexible nonwoven polishing pad comprises the following steps: ultrasonically dispersing an abrasive in an adhesive resin, mixing polyamide fiber, polyester fiber and modified carbon fiber and combing them into a fiber web, impregnating the fiber web with the adhesive resin, and curing the fiber web by heating to obtain a nonwoven polishing pad.

[0021] By adopting the above technical solution, the abrasive is fully impregnated with the adhesive resin, so that the abrasive is evenly dispersed on the non-woven fabric substrate, so that the non-woven fabric substrate and the abrasive are fully combined, and the adhesive resin can strengthen the non-woven fabric substrate.

[0022] In summary, this application has the following beneficial effects: 1. In the present application, polyamide fiber and polyester fiber have good elasticity and strength, and can be used to prepare a non-woven fabric substrate with good wear resistance and elasticity. The adhesive resin is mixed with the abrasive and impregnated into the non-woven fabric substrate, so that the abrasive can be solidified on the non-woven fabric substrate, and the non-woven fabric substrate can be reinforced to improve its strength. The addition of modified carbon fiber can further enhance the mechanical strength and wear resistance of the non-woven fabric substrate. At the same time, the carbon fiber has good thermal conductivity and can conduct and disperse the heat generated during the grinding process, thereby improving the heat resistance of the grinding pad.

[0023] 2. In the present application, after the multi-walled carbon nanotubes are treated with mixed acid, the surface of the multi-walled carbon nanotubes contains carboxyl groups, which improves the dispersibility of the modified carbon nanotubes in the spinning solution, so that the modified carbon nanotubes can form a hybrid structure with the carbon fibers, and the obtained modified carbon fibers have excellent mechanical properties.

[0024] 3. In the present application, the epoxy resin has excellent wear resistance after curing, and the liquid epoxy resin has suitable fluidity and viscosity, so that the abrasive can be evenly distributed throughout the non-woven fabric substrate with the epoxy resin. The addition of modified silica aerogel can increase the viscosity of the epoxy resin after curing and improve its durability. DETAILED DESCRIPTION

[0025] The present application is further described in detail below in conjunction with embodiments.

[0026] Preparation Example 1-6 of Modified Carbon Fiber Preparation Example 1 The preparation method of modified carbon fiber comprises the following steps: adding multi-walled carbon nanotubes to a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1, condensing and refluxing at 115°C for 1.2 hours, washing, filtering and drying to obtain modified carbon nanotubes, dissolving polyacrylonitrile in N,N'-dimethylformamide to obtain a spinning solution with a polyacrylonitrile concentration of 12wt%, ultrasonically dispersing the modified carbon nanotubes in the spinning solution, wherein the added amount of the modified carbon nanotubes is 3wt% of the polyacrylonitrile, performing electrostatic spinning, the spinning voltage is 17kV, the receiving distance is 14cm, the spinning solution flow rate is 0.35mL / h, to obtain modified polyacrylonitrile fibers, heating to 230°C at a speed of 3°C / min and keeping the temperature for 4 hours, cooling naturally, and then heating to 900°C at a speed of 5°C / min and keeping the temperature for 1 hour under the protection of nitrogen, cooling to room temperature, to obtain modified carbon fiber.

[0027] Preparation Example 2 The preparation method of modified carbon fiber comprises the following steps: adding multi-walled carbon nanotubes to a mixed solution of concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1, condensing and refluxing at 120°C for 1h, washing, suction filtering and drying to obtain modified carbon nanotubes, dissolving polyacrylonitrile in N,N'-dimethylformamide to obtain a spinning solution with a polyacrylonitrile concentration of 15wt%, ultrasonically dispersing the modified carbon nanotubes in the spinning solution, wherein the added amount of the modified carbon nanotubes is 5wt% of the polyacrylonitrile, performing electrostatic spinning, the spinning voltage is 20kV, the receiving distance is 16cm, the spinning solution flow rate is 0.5mL / h, to obtain modified polyacrylonitrile fibers, heating to 230°C at a speed of 3°C / min and keeping the temperature for 4h, cooling naturally, and then heating to 1000°C at a speed of 5°C / min and keeping the temperature for 1h under the protection of nitrogen, cooling to room temperature, to obtain modified carbon fiber.

[0028] Preparation Example 3 The difference between Preparation Example 3 and Preparation Example 1 is that in Preparation Example 3, the added amount of the modified carbon nanotubes is 1 wt % of the polyacrylonitrile.

[0029] Preparation Example 4 The difference between Preparation Example 4 and Preparation Example 1 is that in Preparation Example 4, the added amount of the modified carbon nanotubes is 8 wt % of the polyacrylonitrile.

[0030] Preparation Example 5 The difference between Preparation Example 5 and Preparation Example 1 is that in Preparation Example 5, an equal amount of multi-walled carbon nanotubes is used instead of modified carbon nanotubes.

[0031] Preparation Example 6 The difference between Preparation Example 6 and Preparation Example 1 is that in Preparation Example 6, no modified carbon nanotubes are added to the spinning solution.

[0032] Preparation Examples 7-10 of Modified Silica Aerogel Preparation Example 7 The preparation method of modified silica aerogel comprises the following steps: adding 0.08 mL of hydrochloric acid and 0.75 g of hexadecyltrimethylammonium bromide to 15 mL of water and mixing evenly, adding 3.2 mL of methyltriethoxysilane and 1 mL of dimethyldiethoxysilane, magnetically stirring at 20° C. for 2.5 h, adding silica microspheres, and ultrasonically dispersing them evenly, adding 1.5 g of urea, standing at 75° C. to obtain a wet gel, washing, and drying to obtain the modified silica aerogel, wherein the amount of silica microspheres added is 4.89 wt % of the total weight of the modified silica aerogel.

[0033] Preparation Example 8 The preparation method of modified silica aerogel comprises the following steps: adding 0.09 mL of hydrochloric acid and 0.9 g of hexadecyltrimethylammonium bromide to 20 mL of water and mixing evenly, adding 4 mL of methyltriethoxysilane and 1.5 mL of dimethyldiethoxysilane, magnetically stirring at 25° C. for 2 h, adding silica microspheres, and ultrasonically dispersing the mixture evenly, adding 2.2 g of urea, standing at 80° C. to obtain a wet gel, washing, and drying to obtain the modified silica aerogel, wherein the amount of silica microspheres added is 5.32 wt % of the total weight of the modified silica aerogel.

[0034] Preparation Example 9 The difference between Preparation Example 9 and Preparation Example 7 is that in Preparation Example 9, the added amount of silica microspheres is 2.35 wt % of the total weight of the modified silica aerogel.

[0035] Preparation Example 10 The difference between Preparation Example 10 and Preparation Example 7 is that in Preparation Example 10, the added amount of silica microspheres is 7.25 wt % of the total weight of the modified silica aerogel. Example

[0036] Example 1 A rigid-flexible non-woven polishing pad comprises the following raw materials in parts by weight: 50 kg of a non-woven fabric substrate, 8 kg of abrasive and 20 kg of an adhesive resin; the non-woven fabric substrate comprises the following raw materials: polyamide fiber, polyester fiber and modified carbon fiber, the mass ratio of the polyamide fiber, polyester fiber and modified carbon fiber is 1.05:0.98:0.23, the modified carbon fiber is the modified carbon fiber prepared in Preparation Example 1, the abrasive is silicon oxide with an average particle size of 5-200 nm, the adhesive resin comprises the following raw materials in parts by weight: an epoxy resin, an amine curing agent and modified silica aerogel in a mass ratio of 18.36:14.32:1.51, the amine curing agent is ethylenediamine, and the modified silica aerogel is the modified silica aerogel prepared in Preparation Example 7 of the modified silica aerogel.

[0037] The preparation method of the above-mentioned non-woven polishing pad comprises the following steps: dispersing modified silica aerogel in epoxy resin, adding an amine curing agent and mixing evenly to obtain an adhesive resin, ultrasonically dispersing an abrasive in the adhesive resin, mixing polyamide fiber, polyester fiber and modified carbon fiber and combing them into a fiber web, impregnating the adhesive resin, heating to 90°C for curing, and obtaining a non-woven polishing pad.

[0038] Example 2 A rigid-flexible non-woven polishing pad comprises the following raw materials in parts by weight: 60 kg of a non-woven fabric substrate, 12 kg of an abrasive and 25 kg of an adhesive resin; the non-woven fabric substrate comprises the following raw materials: polyamide fiber, polyester fiber and modified carbon fiber, the mass ratio of the polyamide fiber, polyester fiber and modified carbon fiber is 1.36:1.21:0.34, the modified carbon fiber is the modified carbon fiber obtained in Preparation Example 2, the abrasive is diamond with an average particle size of 5-200 nm, the adhesive resin comprises the following raw materials in parts by weight: an epoxy resin, an amine curing agent and modified silica aerogel in a mass ratio of 21.34:15.26:1.89, the amine curing agent is ethylenediamine, and the modified silica aerogel is the modified silica aerogel obtained in Preparation Example 8 of the modified silica aerogel.

[0039] The preparation method of the above-mentioned non-woven polishing pad comprises the following steps: dispersing modified silica aerogel in epoxy resin, adding an amine curing agent and mixing evenly to obtain an adhesive resin, ultrasonically dispersing an abrasive in the adhesive resin, mixing polyamide fiber, polyester fiber and modified carbon fiber and combing them into a fiber web, impregnating the adhesive resin, heating to 90°C for curing, and obtaining a non-woven polishing pad.

[0040] Example 3 The difference between Example 3 and Example 1 is that in Example 3, the mass ratio of polyamide fiber, polyester fiber and modified carbon fiber is 1.05:0.52:0.98.

[0041] Example 4 The difference between Example 4 and Example 1 is that in Example 4, the mass ratio of polyamide fiber, polyester fiber and modified carbon fiber is 1.05:1.98:0.12.

[0042] Example 5 The difference between Example 5 and Example 1 is that in Example 5, the modified carbon fiber is the modified carbon fiber prepared in Preparation Example 3.

[0043] Example 6 The difference between Example 6 and Example 1 is that in Example 6, the modified carbon fiber is the modified carbon fiber prepared in Preparation Example 4.

[0044] Example 7 The difference between Example 7 and Example 1 is that in Example 7, the modified carbon fiber is the modified carbon fiber prepared in Preparation Example 5.

[0045] Example 8 The difference between Example 8 and Example 1 is that in Example 8, the modified carbon fiber is the modified carbon fiber prepared in Preparation Example 6.

[0046] Example 9 The difference between Example 9 and Example 1 is that in Example 9, the modified silica aerogel is the modified silica aerogel prepared in Preparation Example 9.

[0047] Example 10 The difference between Example 10 and Example 1 is that in Example 10, the modified silica aerogel is the modified silica aerogel prepared in Preparation Example 10.

[0048] Embodiment 11 The difference between Example 11 and Example 1 is that in Example 11, the mass ratio of epoxy resin, amine curing agent and modified silica aerogel is 18.36:14.32:0.56.

[0049] Example 12 The difference between Example 12 and Example 1 is that in Example 12, the mass ratio of epoxy resin, amine curing agent and modified silica aerogel is 18.36:14.32:2.65.

[0050] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in Comparative Example 1, no modified carbon fiber is added to the non-woven fabric substrate.

[0051] Detection Methods A non-woven abrasive pad was prepared according to the raw materials and methods of Examples 1-12 and Comparative Example 1, and the hardness and heat resistance of the non-woven abrasive pad were tested. The hardness was tested according to ASTM D2240-2015, and a grinding test was performed. The process parameters of the specific test method are as follows: the polishing liquid is a 5 μm particle size diamond polishing liquid; the equipment is a single plane grinder; the test workpiece is a φ30*T2mm standard block; the processing time is 3 min; the wear mass of the standard block and the temperature of the grinding pad within 20 s after grinding are recorded, and the results are recorded in Table 1.

[0052] Table 1 Performance test of non-woven abrasive pad project Shore Hardness Wear mass / g Temperature / ℃ Example 1 68 0.449 61 Example 2 69 0.454 59 Example 3 58 0.385 72 Example 4 57 0.381 73 Example 5 61 0.399 70 Example 6 52 0.341 82 Example 7 54 0.352 79 Example 8 60 0.408 72 Example 9 63 0.418 63 Example 10 62 0.412 64 Embodiment 11 63 0.417 65 Example 12 64 0.420 63 Comparative Example 1 45 0.292 116 According to Table 1, Examples 1-2 and Comparative Example 1, it can be seen that the hardness and wear quality of Examples 1-2 are improved, and the temperature is reduced, indicating that the polishing pads prepared in Examples 1-2 have good mechanical properties and strength, as well as good heat dissipation and heat resistance. The polyamide fiber and polyester fiber have good elasticity and strength. The non-woven fabric substrate formed by the composite of the two and the modified carbon fiber has excellent mechanical properties and elasticity, good wear resistance, and the modified carbon fiber has good thermal conductivity, thereby improving the thermal conductivity of the non-woven fabric substrate, so that when the non-woven fabric polishing pad is in use, the heat generated by friction can be quickly conducted and diffused, and the heat dissipation is good, thereby improving the heat resistance of the non-woven fabric polishing pad.

[0053] Compared with Example 1, the hardness and wear quality of Example 3-4 are reduced, and the temperature is increased. The mass ratio of polyamide fiber, polyester fiber and carbon fiber is changed in Example 3-4, which shows that there is a synergistic effect among the three. The mass ratio between the three affects the mechanical strength and wear resistance of the non-woven fabric substrate formed after compounding. When the mass ratio changes, the synergistic effect weakens, and the strength and wear resistance of the non-woven fabric substrate decrease.

[0054] Compared with Example 1, the hardness and wear quality of Example 5-6 are reduced, and the temperature is increased. When preparing the modified carbon fiber used in Example 5-6, the addition amount of modified carbon nanotubes in the spinning solution is changed. When the addition amount of modified carbon nanotubes is reduced, the reinforcing effect of the modified carbon nanotubes on the modified carbon fiber is reduced, thereby reducing the mechanical strength of the modified carbon fiber. When the addition amount of modified carbon nanotubes is increased, their concentration in the spinning solution is increased, affecting the spinning effect, and it is not easy to obtain continuous and uniform modified polyacrylonitrile fibers, so that the modified carbon fibers obtained after pre-oxidation and carbonization are discontinuous and have poor uniformity, affecting the mechanical strength and performance of the modified carbon fiber.

[0055] Compared with Example 1, the hardness and wear quality of Examples 7-8 are reduced, and the temperature is increased. When preparing the modified carbon fiber used in Example 7, the multi-walled carbon nanotubes are not subjected to mixed acid treatment, the carboxyl group content on the surface is reduced, and the dispersibility of the multi-walled carbon nanotubes in the spinning solution is reduced, making it easy to agglomerate, affecting the electrospinning effect; when preparing the modified carbon fiber used in Example 8, no modified carbon nanotubes are added to the spinning solution. The modified carbon nanotubes have a reinforcing effect on the modified carbon fiber. When they are not added, the strength and thermal conductivity of the modified carbon fiber are reduced, thereby reducing the wear resistance and heat resistance of the polishing pad.

[0056] Compared with Example 1, the hardness and wear quality of Examples 9-10 are reduced. When preparing the modified silica aerogel used in Examples 9-10, the amount of silica microspheres added was changed. When the amount of silica microspheres added was low, the stacking density of the internal structure of the modified silica aerogel decreased, which reduced the mechanical strength of the modified silica aerogel, thereby reducing the performance of the adhesive resin after curing. When the amount of silica microspheres added was high, the porosity of the modified silica aerogel decreased, which reduced the elasticity of the modified silica aerogel. At the same time, the silica microspheres were prone to agglomeration, which destroyed the organizational structure of the silica aerogel, thereby reducing the wear resistance of the grinding pad.

[0057] Compared with Example 1, the hardness and wear quality of Examples 11-12 are reduced. In Examples 11-12, the amount of modified silica aerogel added in the adhesive resin is changed. When the amount of modified silica aerogel added is low, the reinforcing effect of the modified silica aerogel on the adhesive resin is reduced, resulting in a decrease in the elasticity and wear resistance of the adhesive resin. When the amount of modified silica aerogel added is high, the dispersibility of the modified silica aerogel is reduced, which destroys the organizational structure of the adhesive resin after curing, reduces its mechanical properties, and reduces the wear resistance of the polishing pad.

[0058] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make modifications to the present embodiment without any creative contribution as needed, but such modifications are protected by the patent law as long as they are within the scope of the claims of the present application.

Claims

1. A rigid-flexible nonwoven polishing pad, characterized in that: The method comprises the following raw materials in parts by weight: 50-60 parts of a non-woven fabric substrate, 8-12 parts of an abrasive and 20-25 parts of an adhesive resin; The non-woven fabric substrate comprises the following raw materials: polyamide fiber, polyester fiber and modified carbon fiber.

2. The rigid-flexible nonwoven polishing pad according to claim 1, characterized in that: The mass ratio of the polyamide fiber, the polyester fiber and the modified carbon fiber is (1.05-1.36):(0.98-1.21):(0.23-0.34).

3. The rigid-flexible nonwoven polishing pad according to claim 1, characterized in that: The abrasive is selected from one or more of silicon oxide, aluminum oxide, zirconium oxide, iron oxide, chromium oxide and diamond, and the average particle size of the abrasive is 5-200 nm.

4. The rigid-flexible nonwoven polishing pad according to claim 1, characterized in that: The preparation method of the modified carbon fiber comprises the following steps: adding multi-walled carbon nanotubes to a mixture of concentrated sulfuric acid and concentrated nitric acid, condensing and refluxing at 115-120° C. for 1-1.2 hours, washing, filtering and drying to obtain modified carbon nanotubes, dissolving polyacrylonitrile in N,N'-dimethylformamide to obtain a spinning solution, ultrasonically dispersing the modified carbon nanotubes in the spinning solution, performing electrostatic spinning to obtain modified polyacrylonitrile fibers, and performing pre-oxidation and carbonization to obtain modified carbon fibers.

5. The rigid-flexible nonwoven polishing pad according to claim 4, characterized in that: The added amount of the modified carbon nanotubes is 3-5wt% of polyacrylonitrile.

6. The rigid-flexible nonwoven polishing pad according to claim 1, characterized in that: The adhesive resin comprises the following raw materials in parts by mass: epoxy resin, amine curing agent and modified silica aerogel in a mass ratio of (18.36-21.34):(14.32-15.26):(1.51-1.89).

7. The rigid-flexible nonwoven polishing pad according to claim 6, characterized in that: The preparation method of the modified silica aerogel comprises the following steps: adding hydrochloric acid and hexadecyltrimethylammonium bromide into water and mixing them evenly, adding methyltriethoxysilane and dimethyldiethoxysilane, stirring magnetically for 2-2.5 hours at 20-25°C, adding silica microspheres and dispersing them evenly by ultrasonication, adding urea, standing at 75-80°C to obtain a wet gel, washing, and drying to obtain the modified silica aerogel.

8. The rigid-flexible nonwoven polishing pad according to claim 7, characterized in that: The added amount of the silica microspheres is 4.89-5.32 wt % of the total weight of the modified silica aerogel.

9. The method for preparing the rigid-flexible nonwoven polishing pad according to claims 1-8, characterized in that: The following steps are involved: The abrasive is ultrasonically dispersed in the adhesive resin, polyamide fiber, polyester fiber and modified carbon fiber are mixed and combed into a fiber web, which is then impregnated with the adhesive resin and cured by heating to obtain a non-woven abrasive pad.