Polishing composition as well as preparation method and application thereof

Abstract

The invention discloses a polishing composition as well as a preparation method and application thereof. The polishing composition comprises the following raw materials in percentage by mass: 2%-20% of an abrasive, 0.1%-5% of a dispersing agent, 1%-5% of a humectant, 0.1%-2% of a pH regulator and 68%-96.8% of water, the grinding material comprises silicon dioxide, the silicon dioxide is in an ellipsoidal shape, the primary particle size of the silicon dioxide ranges from 10 nm to 100 nm, the secondary particle size of the silicon dioxide ranges from 0.5 micrometer to 5 micrometers, and the specific surface area of the silicon dioxide ranges from 50 m < 2 > / kg to 120 m < 2 > / kg. The ellipsoidal silicon dioxide serves as an abrasive material, the cutting effect can be remarkably improved, fine polishing of a polished surface is achieved, and the quality of the polished surface and the performance of a device are remarkably improved. Meanwhile, the polishing composition is stable in system, the risk that a substrate is scratched due to the fact that traditional silica sol is prone to crystallization and gelation is avoided, and the service life of the polishing composition is remarkably prolonged.

Description

Technical Field

[0001] This invention relates to the field of surface treatment technology, and in particular to a polishing composition, its preparation method, and its application. Background Technology

[0002] Polishing is a processing method that uses mechanical, chemical, or electrochemical actions to reduce the surface roughness of a workpiece, thereby obtaining a bright and smooth surface. The commonly used polishing process involves using abrasive-containing polishing compounds in conjunction with polishing tools or other polishing media to refine the workpiece surface. The morphology and properties of the abrasive particles in the polishing compound, such as their shape, surface morphology, and hardness, have a significant impact on polishing efficiency and results.

[0003] Silica, due to its superior properties such as high hardness, wear resistance, corrosion resistance, and thermal stability, has been widely used as an abrasive in polishing. However, in the process of precision polishing high-hardness material surfaces, traditional silica particles or silica sols still fall short of achieving efficient polishing and meeting surface requirements. Furthermore, traditional silica sols are difficult to control in polishing products, and blending them with other additives can easily disrupt the colloidal system, leading to gelation and affecting polishing performance and lifespan. Therefore, the limitations of current silica or silica sol polishing products, to some extent, restrict the application of related materials and the development of high-performance devices. Summary of the Invention

[0004] Therefore, it is necessary to provide a polishing composition that can achieve precision polishing of high-hardness material surfaces, while also possessing excellent stability and service life.

[0005] In a first aspect, the present invention provides a polishing composition, wherein, by mass percentage, the raw material composition of the polishing composition comprises 2%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster and 68%-96.8% water;

[0006] The abrasive comprises silicon dioxide, which is ellipsoidal in shape. The median primary particle size (D50) of the silicon dioxide is 10 nm-100 nm, the median secondary particle size (D50) is 0.5 μm-5 μm, and the specific surface area of ​​the silicon dioxide is 50 m². 2 / kg-120m 2 / kg.

[0007] In some embodiments, the dispersant comprises at least one selected from sodium pyrophosphate, potassium phosphate, sodium phosphate, sodium hexametaphosphate, sodium polyacrylate, sodium dodecylbenzenesulfonate, sodium alginate, sodium carboxymethyl cellulose, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, and disodium succinate; and / or,

[0008] The humectant comprises at least one selected from ethylene glycol, propylene glycol, n-butanol, isobutanol, 2-butanol, 1,4-butanediol, 1,5-pentanediol, glycerol, triethylene glycol, diethylene glycol methyl ether, triethylene glycol ethyl ether, tetraethylene glycol ethyl ether, and sorbitol; and / or,

[0009] The pH adjuster comprises at least one selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, ethylenediamine, diethanolamine, triethanolamine, dipropylamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, diethylenetriamine, and triethylenetetramine; and / or,

[0010] The resistivity of the water is ≥18 mΩ·cm; and / or the pH of the polishing composition is 10-13.

[0011] In some embodiments, the polishing composition comprises, by weight percentage, 5%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster, and 68%-93.8% water.

[0012] In some embodiments, the median primary particle size D50 of the silicon dioxide is 20nm-60nm, and the median secondary particle size D50 of the silicon dioxide is 1.5μm-4.5μm.

[0013] In some embodiments, the method for preparing the silicon dioxide includes the following steps:

[0014] An inorganic dispersant and an organic dispersant are added to water glass, mixed, heat-treated, and stirred to form a first mixture; the inorganic dispersant includes sulfates and phosphates.

[0015] While stirring, the first mixture is added to the sulfuric acid solution in batches to carry out the reaction. When the pH of the reaction system is 2.5-3.5, the addition of the first mixture to the sulfuric acid solution is stopped, and the reaction system is aged to form the second mixture.

[0016] The second mixture is subjected to solid-liquid separation and washing to form a slurry. The slurry is then refined at least in two stages to prepare silica.

[0017] In some embodiments, the preparation process of the silicon dioxide also satisfies at least one of the following conditions (1) to (10):

[0018] (1) The concentration of the water glass is 0.5 mol / L-1.5 mol / L, and the modulus of the water glass is 2-4;

[0019] (2) The inorganic dispersant is added at a mass of 0.5%-1.2% of the water glass, and the organic dispersant is added at a mass of 0.01%-0.5% of the water glass;

[0020] (3) The mass ratio of the inorganic dispersant to the organic dispersant is (2-7):1;

[0021] (4) The mass ratio of the sulfate to the phosphate is (0.8-5):1;

[0022] (5) The sulfate includes sodium sulfate, the phosphate includes sodium metaphosphate; the organic dispersant includes polyethylene glycol;

[0023] Optionally, the average molecular weight of the polyethylene glycol is 400-4000;

[0024] (6) The heat treatment temperature is 60℃-80℃;

[0025] (7) The stirring speed is 400rpm-800rpm;

[0026] (8) The first mixture is added to the sulfuric acid solution in batches at a rate of 3L / h-5L / h.

[0027] (9) The concentration of the sulfuric acid solution is 0.2 mol / L-0.5 mol / L, and the temperature of the sulfuric acid solution is 60℃-80℃;

[0028] (10) The aging temperature is 60℃-80℃ and the aging time is 1h-3h; during the washing process, the washing is stopped when the conductivity of the waste liquid generated by washing is <2000μs / cm.

[0029] In some embodiments, during the secondary refinement process, the first stage of refinement is achieved by abrasive processing, resulting in silica particles with a particle size of 5μm-15μm. The second stage of refinement is achieved by airflow abrasive processing, with an airflow abrasive pressure of 0.6rpm-1.2MPa and a classifying wheel speed of 10000rpm-20000rpm, resulting in silica particles with a particle size of 10nm-5μm.

[0030] Optionally, the median particle size D50 of the primary particle size of the second-stage refined silica is 10nm-100nm, and the median particle size D50 of the secondary particle size is 0.5μm-5μm.

[0031] In some embodiments, the polishing composition may be in the form of a solution, suspension, emulsion, spray, foam, paste, or powder.

[0032] Secondly, the present invention also provides a method for preparing a polishing composition, comprising the following steps:

[0033] Under stirring conditions, a pH adjuster, dispersant, and humectant are added to water for dissolution, and silica is added for mixing to prepare a polishing composition.

[0034] Thirdly, the present invention also provides the application of a polishing composition in the sapphire processing process, said polishing composition comprising the polishing composition provided in the first aspect.

[0035] Compared with the prior art, the beneficial effects of the technical solution of the present invention include:

[0036] This invention provides a polishing composition comprising an abrasive, a dispersant, a humectant, a pH adjuster, and water. The abrasive used is ellipsoidal silica, which significantly enhances the cutting action on the material to be polished, substantially increasing the material removal rate compared to regularly shaped spherical silica. Furthermore, the ellipsoidal silica used in this invention has a small particle size, with a median primary particle size (D50) of 10 nm-100 nm and a median secondary particle size (D50) of 0.5 μm-5 μm. The silica has a specific surface area of ​​50 m². 2 / kg-120m 2 / kg, which can achieve fine polishing of the polished surface, significantly improve the quality of the polished surface, and the silica of the particle size range is compounded with other additives in a specific ratio range to form a stable polishing composition system, avoiding the risk of crystallization and gelation of traditional silica sol causing matrix scratches, and also significantly extending the service life of the polishing composition. Detailed Implementation

[0037] To facilitate understanding of the present invention, preferred embodiments are provided below to provide a more complete description of the invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to enable a thorough and complete understanding of the disclosure of the present invention.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0039] As used herein, "optional," "optional," and "optional" refer to either "with" or "without" parallel options. If multiple "optional" entries appear in a technical solution, each "optional" entry is independent unless otherwise specified and there are no contradictions or mutual constraints. The term "and / or" as used herein includes any and all combinations of one or more related listed items. Unless otherwise specified, "multiple," "multiple," etc., as used herein refer to a quantity greater than 2 or equal to 2; for example, "one or more" indicates one, two, or more than two. In open-ended technical features or solutions described herein using words such as "containing," "including," and "comprising," unless otherwise specified, additional members beyond the listed members are not excluded. This can be considered as providing both a closed-ended feature or solution consisting of the listed members and an open-ended feature or solution that includes additional members beyond the listed members.

[0040] In this invention, the terms "first aspect," "second aspect," "third aspect," "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," "fourth," etc., serve only as a non-exhaustive enumeration and should be understood not to constitute a closed limitation on the quantity.

[0041] Unless otherwise specified, all embodiments and optional embodiments of the present invention can be combined with each other to form new technical solutions.

[0042] Sapphire, commonly known as corundum, is a multifunctional oxide that combines excellent physical and chemical properties. It possesses superior thermal, electrical, dielectric, wear-resistant, durable, chemically stable, thermally conductive, transparent, high-temperature stable, electrically insulating, and radiation-resistant characteristics. It is widely used in military, aerospace, information, optics, superconductivity, communications, defense, and other fields; for example, as a substrate for solid-state lasers, infrared windows, semiconductor chips, and light-emitting diodes (LEDs); infrared devices in missiles, submarines, satellites, high-energy detection instruments, and high-power laser instruments; infrared and microwave window systems; light-emitting diodes (LEDs), laser diodes (LDs); light transmission windows for ultraviolet to near-infrared light; lens materials; screen materials for smart terminal devices; and precision wear-resistant bearing materials. However, sapphire's high hardness makes surface polishing difficult, which affects its performance in high-end devices and limits their application capabilities.

[0043] Traditionally, sapphire polishing agents primarily use silica sol. The nano-SiO2 particles in silica sol possess moderate Mohs hardness, effectively removing surface material from sapphire through rolling and micro-cutting actions during polishing, while avoiding scratches on the substrate. However, traditional silica sol still presents several technical challenges. The relatively large particle size results in weak cutting force, leading to low polishing efficiency and impacting industrial production efficiency. Furthermore, the silica sol system suffers from poor stability, easily affected by additives or environmental factors, potentially causing crystallization, gelation, and failure, thus affecting its polishing effect and lifespan.

[0044] Based on this, the present invention aims to provide a composite polishing product containing silica abrasive, which can achieve efficient polishing of high-hardness material surfaces, obtain precise polishing effects, and at the same time have excellent stability, convenient construction and long service life.

[0045] In a first aspect, the present invention provides a polishing composition, wherein, by mass percentage, the raw material composition of the polishing composition comprises 2%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster and 68%-96.8% water;

[0046] The abrasive comprises silicon dioxide, which is ellipsoidal in shape. The silicon dioxide is prepared by precipitation. The median primary particle size (D50) of the silicon dioxide is 10 nm-100 nm, and the median secondary particle size (D50) is 0.5 μm-5 μm. The specific surface area of ​​the silicon dioxide is 50 m². 2 / kg-120m 2 / kg.

[0047] This invention provides a polishing composition containing specific silica abrasives, wherein the silica has a unique ellipsoidal shape. Compared to traditional regular spherical silica, ellipsoidal silica has stronger cutting force, greatly improving the removal efficiency of surface materials and maintaining excellent polishing efficiency even at low concentrations. Simultaneously, the silica has a small particle size, which significantly improves the fine polishing of material surfaces and contributes to the stability of the polishing composition. Furthermore, the silica has suitable hardness, preventing scratches on the material matrix and ensuring the smoothness and polishing effect of the polished surface.

[0048] In some embodiments, the polishing composition comprises, by weight percentage, 5%-20% abrasive, 0.1%-1% dispersant, 1%-5% humectant, 0.1%-1% pH adjuster, and 73%-93.8% water.

[0049] In some embodiments, the dispersant includes at least one of sodium pyrophosphate, potassium phosphate, sodium phosphate, sodium hexametaphosphate, sodium polyacrylate, sodium dodecylbenzenesulfonate, sodium alginate, sodium carboxymethyl cellulose, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, and disodium succinate.

[0050] In some embodiments, the humectant includes at least one selected from ethylene glycol, propylene glycol, n-butanol, isobutanol, 2-butanol, 1,4-butanediol, 1,5-pentanediol, glycerol, triethylene glycol, diethylene glycol methyl ether, triethylene glycol ethyl ether, tetraethylene glycol ethyl ether, and sorbitol.

[0051] In some embodiments, the pH adjuster includes at least one of potassium hydroxide, sodium hydroxide, lithium hydroxide, ethylenediamine, diethanolamine, triethanolamine, dipropylamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, diethylenetriamine, and triethylenetetramine.

[0052] In some embodiments, the resistivity of the water is ≥18 mΩ·cm. In the polishing composition system provided in this invention, water serves as a dispersion solvent, and its resistivity has a certain impact on the stability of the system and the polishing effect. In this invention, when the resistivity of the water is lower than 18 mΩ·cm, it will affect the charge distribution on the surface of the silica particles, causing some silica abrasive to agglomerate and settle, thereby leading to the failure of the polishing composition, and even scratching the material matrix during the polishing process, making fine polishing impossible. Further, the resistivity of the water is 18 mmΩ·cm-18.25 mΩ·cm.

[0053] In some embodiments, the polishing composition comprises, by weight percentage, 5%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster, and 68%-93.8% water.

[0054] In some embodiments, the pH of the polishing composition is 10-13, including but not limited to 10, 10.5, 11, 11.5, 12, 12.5, 13, or any combination thereof and values ​​within that range. In this invention, the pH of the system is controlled by a pH adjuster. Within the specified pH range, silica particles rapidly form a softened hydrated layer on the material surface. This synergistic effect of mechanical and chemical action significantly improves the material removal rate while achieving atomic-level surface smoothness, meeting the stringent surface quality requirements of high-performance devices.

[0055] In some embodiments, the silica is prepared by precipitation, wherein the median primary particle size D50 of the silica is 10 nm-100 nm, and the median secondary particle size D50 is 0.5 μm-5 μm. Further, the median primary particle size D5 of the silica is 20 nm-60 nm, and the median secondary particle size D5 of the silica is 0.5 μm-4.5 μm. Even further, the median primary particle size D5 of the silica is 20 nm-50 nm, and the median secondary particle size D5 of the silica is 1.5 μm-3.5 μm.

[0056] In some embodiments, the method for preparing the silicon dioxide includes the following steps:

[0057] S10. Add inorganic and organic dispersants to water glass, mix, heat treat, and stir to form a first mixture; the inorganic dispersants include sulfates and phosphates.

[0058] S20. While stirring, the first mixture is added to the sulfuric acid solution in batches for reaction. When the pH of the reaction system is 2.5-3.5, the addition of the first mixture to the sulfuric acid solution is stopped, and the reaction system is aged to form a second mixture.

[0059] S30. The second mixture is subjected to solid-liquid separation and washing to form a slurry. The slurry is then refined at least in two stages to prepare silica.

[0060] By dispersing and stabilizing water glass with inorganic and organic dispersants, it reacts with sulfuric acid solution to form small ellipsoidal silica particles. These particles can be used in surface polishing processes to achieve precise and efficient polishing of high-hardness material surfaces.

[0061] In some embodiments, the concentration of the water glass is 0.5 mol / L to 1.5 mol / L, including but not limited to 0.5 mol / L, 0.7 mol / L, 0.9 mol / L, 1.1 mol / L, 1.3 mol / L, 1.5 mol / L, or any of the foregoing ranges and values ​​within those ranges.

[0062] In some embodiments, the modulus of the water glass is 2-4, including but not limited to 2, 2.2, 2.5, 2.8, 3, 3.2, 3.5, 3.8, 4, or any combination thereof and values ​​within that range.

[0063] As a non-limiting example, the sulfate includes sodium sulfate, and the phosphate includes sodium metaphosphate. As a non-limiting example, the sodium metaphosphate includes sodium hexametaphosphate. This invention, by using both sulfate and phosphate as inorganic dispersants, can further improve the control of silica particle size during the reaction process. Simultaneously, the use of phosphate can also serve as a component of the polishing slurry system, thereby improving the stability and uniformity of silica in the polishing slurry, and further enhancing its polishing effect.

[0064] In some embodiments, the mass ratio of the sulfate to the phosphate is (0.8-5):1, including but not limited to 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1 or any of the foregoing ranges and values ​​within those ranges.

[0065] In some embodiments, the organic dispersant includes polyethylene glycol (PEG). The ether bonds in the PEG molecule can form hydrogen bonds with the hydroxyl groups on the surface of silica particles, thereby inducing precipitated silica to form an ellipsoidal morphology. This specific morphology of silica effectively reduces the risk of scratching the material surface during polishing and improves the precision polishing effect. Compared to spherical silica abrasives, the ellipsoidal morphology prepared by this invention provides more efficient and precise polishing.

[0066] In some embodiments, the average molecular weight of the polyethylene glycol is 400-4000; further, the average molecular weight of the polyethylene glycol is 600-2000; and even further, the average molecular weight of the polyethylene glycol is 600-800. By controlling the molecular weight of the polyethylene glycol, the dispersibility and stability of the composite dispersant can be controlled, and the content of hydrogen bonds formed between the polyethylene glycol and the hydroxyl groups on the surface of silica particles can be controlled, thereby optimizing the shape and surface morphology of the silica particles.

[0067] In some embodiments, the inorganic dispersant is added at a mass of 0.5%-1.2% of the water glass, including but not limited to 0.5%, 0.6%, 0.8%, 1%, 1.2%, or any combination thereof and values ​​within that range.

[0068] In some embodiments, the added organic dispersant is 0.01%-0.5% of the water glass, including but not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, or any combination thereof and values ​​within that range.

[0069] In some embodiments, the mass ratio of the inorganic dispersant to the organic dispersant is (2-7):1, including but not limited to 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, or any combination thereof and values ​​within that range. This invention, by controlling the ratio of the inorganic and organic dispersants, can optimize the dispersibility and stability of water glass solutions, promote the formation of silica with specific morphologies, and simultaneously control particle size. Furthermore, the composite dispersion system formed using inorganic and organic dispersants can significantly reduce the amount of dispersant used.

[0070] In some embodiments, the heat treatment temperature is 60°C-80°C, including but not limited to 60°C, 65°C, 70°C, 75°C, 80°C or any combination thereof and values ​​within that range.

[0071] In some embodiments, the stirring speed is 400 rpm to 800 rpm, including but not limited to 400 rpm, 500 rpm, 600 rpm, 700 rpm, 800 rpm or any of the foregoing ranges and values ​​within that range.

[0072] In some embodiments, the first mixture is added to the sulfuric acid solution in batches at a rate of 3 L / h to 5 L / h, including but not limited to 3 L / h, 3.5 L / h, 4 L / h, 4.5 L / h, 5 L / h, or any combination thereof and values ​​within that range. It is understood that the addition rate of the first mixture to the sulfuric acid solution is uniform. This invention controls the addition rate of the water glass mixture, thereby regulating the dispersibility and morphology of silica particles during particle formation, such as reducing particle agglomeration, while also controlling particle size and production efficiency. Adjusting the addition rate according to the composition of the water glass mixture better achieves the aforementioned technical effects.

[0073] In some embodiments, the concentration of the sulfuric acid solution is 0.2 mol / L to 0.5 mol / L, including but not limited to 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, or any of the foregoing ranges and values ​​within those ranges.

[0074] In some embodiments, the temperature of the sulfuric acid solution is 60°C-80°C, including but not limited to 60°C, 65°C, 70°C, 75°C, 80°C or any combination thereof and values ​​within that range.

[0075] In some embodiments, the aging temperature is 60°C-80°C, including but not limited to 60°C, 65°C, 70°C, 75°C, 80°C or any combination thereof and values ​​within that range.

[0076] In some embodiments, washing is stopped when the conductivity of the waste liquid generated during washing is <2000 μs / cm.

[0077] In some embodiments, the aging time is 1h-3h, including but not limited to 1h, 1.5h, 2h, 2.5h, 3h or any combination thereof and values ​​within that range.

[0078] In some embodiments, during the secondary refinement process, the first stage of refinement employs abrasive grinding, while the second stage employs airflow abrasive crushing. This invention further optimizes particle crushing and grading by combining abrasive grinding and airflow abrasive crushing in a dual-crushing process, resulting in a more concentrated particle size distribution and more precise particle size control in the final product.

[0079] In some embodiments, the airflow breaking pressure of the airflow breaking process is 0.6MPa-1.2MPa, including but not limited to 0.6MPa, 0.7MPa, 0.8MPa, 0.9MPa, 1MPa, 1.1MPa, 1.2MPa or any of the foregoing ranges and values ​​within that range.

[0080] In some embodiments, the speed of the stage wheel in the airflow abrasion process is 10,000 rpm to 20,000 rpm, including but not limited to 10,000 rpm, 12,000 rpm, 14,000 rpm, 16,000 rpm, 18,000 rpm, 20,000 rpm or any of the foregoing ranges and values ​​within that range.

[0081] In some embodiments, the median particle size D50 of the first-stage refined silica is 5μm-15μm, including but not limited to 5μm, 8μm, 10μm, 12μm, 15μm or any of the foregoing ranges and values ​​within that range.

[0082] In some embodiments, the median particle size D50 of the second-stage refined silica is 10nm-5μm, including but not limited to 10nm, 20nm, 30nm, 50nm, 80nm, 100nm, 200nm, 500nm, 800nm, 1μm, 2μm, 3μm, 4μm, 5μm or any of the foregoing ranges and values ​​within that range.

[0083] In some embodiments, the median primary particle size D50 of the second-stage refined silica is 10 nm-100 nm, and the median secondary particle size D50 is 0.5 μm-5 μm. Further, the median primary particle size D50 of the second-stage refined silica is 20 nm-60 nm, and the median secondary particle size D50 is 1.5 μm-4.5 μm. Even further, the median primary particle size D50 of the second-stage refined silica is 20 nm-50 nm, and the median secondary particle size D50 is 1.5 μm-3.5 μm.

[0084] In some embodiments, the specific surface area of ​​the silicon dioxide is 50 m². 2 / kg-120m 2 / kg, including but not limited to 50m 2 / kg, 60m 2 / kg, 70m 2 / kg, 80m 2 / kg, 90m 2 / kg, 100m 2 / kg, 110m 2 / kg, 120m 2 / kg or any of the aforementioned ranges and values ​​within that range.

[0085] It is understood that both the primary particle size and the secondary particle size are median particle size D50.

[0086] It is understood that the particle size or median particle size mentioned in this invention are particle size dimensions measured using a laser particle size analyzer.

[0087] In some embodiments, the polishing composition may be in the form of a solution, suspension, emulsion, spray, foam, paste, or powder.

[0088] Secondly, the present invention also provides a method for preparing a polishing composition, comprising the following steps:

[0089] Under stirring conditions, a pH adjuster, dispersant, and humectant are added to water for dissolution, and silica is added for mixing to prepare a polishing composition.

[0090] Thirdly, the present invention also provides the application of a polishing composition in the sapphire processing process, said polishing composition comprising the polishing composition provided in the first aspect.

[0091] It should be noted that the experimental methods in the following embodiments of the present invention, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All commonly used chemical reagents used in the embodiments are commercially available products, or can be prepared by those skilled in the art using known methods.

[0092] The resistivity of ultrapure water is 18.25 mΩ·cm.

[0093] Commercially available silica sol 1: Silica sol from Shandong Baite New Materials Co., Ltd., with a median particle size of 80-120nm, pH of 10, and a solid content of 40wt%.

[0094] Commercially available silica sol 2: Silica sol from Shandong Baite New Materials Co., Ltd., with a median particle size of 60-80nm, pH of 10, and a solid content of 45wt%.

[0095] Commercially available silica sol 3: Silica sol from Guangdong Huierte Nanotechnology Co., Ltd., with a median particle size of 80-120nm, pH of 10, and a solid content of 42wt%.

[0096] Preparation of abrasive 1:

[0097] Slowly add 50g of sodium sulfate, 15g of sodium hexametaphosphate, and 10g of PEG600 to 10kg of water glass (0.7mol / L, modulus 3.2). Heat to 70℃, turn on the stirring device, and set the stirring speed of the stirring device to 500rpm to form the first mixture.

[0098] Under continuous stirring at 500 rpm, 22 L of 0.45 mol / L dilute sulfuric acid solution was added to the reactor and the temperature was raised to 70 °C.

[0099] The first mixture was slowly added to the above-mentioned 70°C dilute sulfuric acid solution at a rate of 4 L / h. When the pH value was 3.0, the addition of the first mixture was stopped, and the mixture was stirred and aged for 2 hours to form the second mixture. The second mixture was then filtered to obtain a filter cake.

[0100] The filter cake was washed multiple times by centrifugation with ultrapure water. Washing was stopped when the conductivity of the centrifugal waste liquid was less than 2000 μs / cm. The slurry was then sand-milled to obtain a silica slurry with a median particle size D50 of 10 μm. The silica slurry was then subjected to air-flow drying and crushing at a pressure of 0.8 MPa and a classifying wheel speed of 10000 rpm to obtain ellipsoidal silica with a primary particle size median particle size D50 of 35 nm and a secondary particle size median particle size D50 of 3 μm.

[0101] Preparation of abrasive 2:

[0102] Slowly add 50g of sodium sulfate, 30g of sodium hexametaphosphate, and 20g of PEG600 to 10kg of water glass (0.7mol / L, modulus 3.2). Heat to 70℃, turn on the stirring device, and set the stirring speed of the stirring device to 600rpm to form the first mixture.

[0103] Under continuous stirring at 600 rpm, 22 L of 0.45 mol / L dilute sulfuric acid solution was added to the reactor and the temperature was raised to 70 °C.

[0104] The first mixture was slowly added to the above-mentioned 70°C dilute sulfuric acid solution at a rate of 4 L / h. When the pH value was 3.0, the addition of the first mixture was stopped, and the mixture was stirred and aged for 2 hours to form the second mixture. The second mixture was then filtered to obtain a filter cake.

[0105] The filter cake was washed multiple times by centrifugation with ultrapure water. Washing was stopped when the conductivity of the centrifugal waste liquid was less than 2000 μs / cm. The slurry was then milled to obtain a silica slurry with a particle size of 10 μm. The silica slurry was then subjected to airflow drying and crushing at a pressure of 0.8 MPa and a classifier wheel speed of 15000 rpm to obtain ellipsoidal silica with a primary median particle size D50 of 20 nm and a secondary median particle size D50 of 1.5 μm.

[0106] Preparation of abrasive 3:

[0107] Slowly add 50g of sodium sulfate, 60g of sodium hexametaphosphate, and 40g of PEG600 to 10kg of water glass (0.7mol / L, modulus 3.2). Heat to 70℃, turn on the stirring device, and set the stirring speed of the stirring device to 500rpm to form the first mixture.

[0108] Under continuous stirring at 500 rpm, 22 L of 0.45 mol / L dilute sulfuric acid solution was added to the reactor and the temperature was raised to 70 °C.

[0109] The first mixture was slowly added to the above-mentioned 70°C dilute sulfuric acid solution at a rate of 4 L / h. When the pH value was 3.0, the addition of the first mixture was stopped, and the mixture was stirred and aged for 2 hours to form the second mixture. The second mixture was then filtered to obtain a filter cake.

[0110] The filter cake was washed multiple times by centrifugation with ultrapure water. Washing was stopped when the conductivity of the centrifugal waste liquid was less than 2000 μs / cm. The slurry was then milled to obtain a silica slurry with a particle size of 10 μm. The silica slurry was then subjected to airflow drying and crushing at a pressure of 0.75 MPa and a classifying wheel speed of 10000 rpm to obtain ellipsoidal silica with a primary median particle size D50 of 50 nm and a secondary median particle size D50 of 3.5 μm.

[0111] Example 1

[0112] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0113] Polishing slurry formula:

[0114]

[0115] Preparation of polishing slurry: Sodium hydroxide, sodium pyrophosphate and glycerol were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 min to prepare polishing slurry with a pH of 12.

[0116] Example 2

[0117] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0118] Polishing slurry formula:

[0119]

[0120] Preparation of polishing slurry: Tetramethylammonium hydroxide, disodium ethylenediaminetetraacetate, sodium hexametaphosphate and sorbitol were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 min to prepare polishing slurry with a pH of 11.8.

[0121] Example 3

[0122] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0123] Polishing slurry formula:

[0124]

[0125] Preparation of polishing slurry: Sodium hydroxide, sodium phosphate and ethylene glycol were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 min to prepare polishing slurry with a pH of 12.3.

[0126] Example 4

[0127] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0128] Polishing slurry formula:

[0129]

[0130] Preparation of polishing slurry: Lithium hydroxide, disodium ethylenediaminetetraacetate, triethanolamine and triethylene glycol ethyl ether were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 min to prepare the polishing slurry. The pH of the polishing slurry was 12.2.

[0131] Example 5

[0132] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0133] Polishing slurry formula:

[0134]

[0135] Preparation of polishing slurry: Sodium hydroxide, sodium phosphate and ethylene glycol were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 minutes to prepare the polishing slurry. The pH of the polishing slurry was 12.0.

[0136] Example 6

[0137] This embodiment provides a polishing slurry and its preparation method. The specific preparation steps are as follows:

[0138] Polishing slurry formula:

[0139]

[0140] Preparation of polishing slurry: Sodium hydroxide, sodium phosphate and ethylene glycol were added sequentially to ultrapure water under stirring conditions. After stirring until completely dissolved, abrasive 1 was added and stirring was continued for 30 min to prepare polishing slurry with a pH of 12.5.

[0141] Example 7

[0142] The difference between this embodiment and embodiment 3 is that abrasive 1 is replaced by an equal amount of abrasive 2, while the other components and steps are the same as in embodiment 3.

[0143] Example 8

[0144] The difference between this embodiment and embodiment 3 is that abrasive 1 is replaced by an equal amount of abrasive 3, while the other components and steps are the same as in embodiment 3.

[0145] Comparative Example 1

[0146] The difference between this comparative example and Example 3 is the abrasive. In this comparative example, an equal amount of Evonik Industrial Group's precipitated silica (SIPERNAT-268) is used to replace abrasive 1. All other components and steps are the same as in Example 3.

[0147] Experimental Example 1

[0148] The polishing performance of the polishing slurries prepared in Examples 1-8 and Comparative Example 1, and commercially available silica sol, was tested using the following specific test methods:

[0149] Polishing effect tests were conducted on sapphire test blocks (30mm×30mm×10mm) using the polishing slurry prepared in the above embodiments and comparative examples, as well as three sets of commercially available silica sols. Chemical mechanical polishing was performed under the same conditions on a single-sided polishing machine using polyurethane polishing cloth. The number of test blocks in a single test was 4.

[0150] The polishing conditions were as follows: polishing liquid volume 3kg, pressure 5.75kg, large disc rotation speed 60r / min, small disc rotation speed 40r / min, flow rate mL / min, and polishing time 1h.

[0151] The polished sapphire test blocks were washed and dried, and then the surface morphology and polishing rate were measured. The specific results are shown in Table 1.

[0152] Table 1: Polishing rate and polishing effect of sapphire surface

[0153] Polishing fluid sample Removal rate (μm / h) Surface roughness (nm) Example 1 5.71 0.29 Example 2 4.76 0.21 Example 3 7.48 0.34 Example 4 6.01 0.23 Example 5 3.77 0.29 Example 6 8.65 0.31 Example 7 6.34 0.24 Example 8 9.94 0.38 Comparative Example 1 3.17 0.24 Commercially available silica sol 4.06 0.23 Commercially available silica sol II 3.78 0.18 Commercially available silica sol 3.92 0.25

[0154] As shown in Table 1, the polishing slurry provided by this invention exhibits excellent polishing efficiency and rate for sapphire, achieving a faster polishing rate and better results compared to commercially available precipitated silica and commercially available silica sol. Furthermore, the silica prepared in Examples 1-4 polishes sapphire more effectively than the silica prepared in Examples 5-7.

[0155] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0156] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A polishing composition, characterized in that, The polishing composition comprises, by weight percentage, 2%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster, and 68%-96.8% water; The abrasive comprises silicon dioxide, which is ellipsoidal in shape. The silicon dioxide is prepared by precipitation. The primary median particle size (D50) of the silicon dioxide is 10 nm-100 nm, the secondary median particle size (D50) is 0.5 μm-5 μm, and the specific surface area of ​​the silicon dioxide is 50 m². 2 / kg-120m 2 / kg.

2. The polishing composition according to claim 1, characterized in that, The dispersant comprises at least one selected from sodium pyrophosphate, potassium phosphate, sodium phosphate, sodium hexametaphosphate, sodium polyacrylate, sodium dodecylbenzenesulfonate, sodium alginate, sodium carboxymethyl cellulose, disodium ethylenediaminetetraacetate, tetrasodium ethylenediaminetetraacetate, and disodium succinate; and / or, The humectant comprises at least one selected from ethylene glycol, propylene glycol, n-butanol, isobutanol, 2-butanol, 1,4-butanediol, 1,5-pentanediol, glycerol, triethylene glycol, diethylene glycol methyl ether, triethylene glycol ethyl ether, tetraethylene glycol ethyl ether, and sorbitol; and / or, The pH adjuster comprises at least one selected from potassium hydroxide, sodium hydroxide, lithium hydroxide, ethylenediamine, diethanolamine, triethanolamine, dipropylamine, tripropylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, diethylenetriamine, and triethylenetetramine; and / or, The resistivity of the water is ≥18 mΩ·cm; and / or the pH of the polishing composition is 10-13.

3. The polishing composition according to claim 1 or 2, characterized in that, The polishing composition comprises, by weight percentage, 5%-20% abrasive, 0.1%-5% dispersant, 1%-5% humectant, 0.1%-2% pH adjuster, and 68%-93.8% water.

4. The polishing composition according to claim 1 or 2, characterized in that, The median primary particle size D50 of the silicon dioxide is 20nm-60nm, and the median secondary particle size D50 of the silicon dioxide is 1.5μm-4.5μm.

5. The polishing composition according to claim 1, characterized in that, The method for preparing the silicon dioxide includes the following steps: An inorganic dispersant and an organic dispersant are added to water glass, mixed, heat-treated, and stirred to form a first mixture; the inorganic dispersant includes sulfates and phosphates. While stirring, the first mixture is added to the sulfuric acid solution in batches to carry out the reaction. When the pH of the reaction system is 2.5-3.5, the addition of the first mixture to the sulfuric acid solution is stopped, and the reaction system is aged to form the second mixture. The second mixture is subjected to solid-liquid separation and washing to form a slurry. The slurry is then refined at least in two stages to prepare silica.

6. The polishing composition according to claim 5, characterized in that, The preparation process of the silicon dioxide also satisfies at least one of the following conditions (1) to (10): (1) The concentration of the water glass is 0.5 mol / L-1.5 mol / L, and the modulus of the water glass is 2-4; (2) The inorganic dispersant is added at a mass of 0.5%-1.2% of the water glass, and the organic dispersant is added at a mass of 0.01%-0.5% of the water glass; (3) The mass ratio of the inorganic dispersant to the organic dispersant is (2-7):1; (4) The mass ratio of the sulfate to the phosphate is (0.8-5):1; (5) The sulfate includes sodium sulfate, the phosphate includes sodium metaphosphate; the organic dispersant includes polyethylene glycol; Optionally, the average molecular weight of the polyethylene glycol is 400-4000; (6) The heat treatment temperature is 60℃-80℃; (7) The stirring speed is 400rpm-800rpm; (8) The first mixture is added to the sulfuric acid solution in batches at a rate of 3L / h-5L / h. (9) The concentration of the sulfuric acid solution is 0.2 mol / L-0.5 mol / L, and the temperature of the sulfuric acid solution is 60℃-80℃; (10) The aging temperature is 60℃-80℃ and the aging time is 1h-3h; during the washing process, the washing is stopped when the conductivity of the waste liquid generated by washing is <2000μs / cm.

7. The polishing composition according to claim 5 or 6, characterized in that, In the two-stage refinement process, the first stage of refinement adopts a sanding process, and the particle size of the silica after the first stage of refinement is 5μm-15μm. The second stage of refinement adopts an air jet crushing process, with a pressure of 0.6MPa-1.2MPa and a classifying wheel speed of 10000rpm-20000rpm. The median particle size D50 of the silica after the second stage of refinement is 10nm-5μm. Optionally, the median particle size D50 of the primary particle size of the second-stage refined silica is 10nm-100nm, and the median particle size D50 of the secondary particle size is 0.5μm-5μm.

8. The polishing composition according to claim 1, characterized in that, The polishing composition may be in the form of a solution, suspension, emulsion, spray, foam, paste, or powder.

9. A method for preparing the polishing composition according to any one of claims 1 to 8, characterized in that, Includes the following steps: Under stirring conditions, a pH adjuster, dispersant, and humectant are added to water for dissolution, and silica is added for mixing to prepare a polishing composition.

10. The application of a polishing composition in the sapphire processing process, characterized in that, The polishing composition includes the polishing composition according to any one of claims 1 to 8.

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