Sodium bicarbonate-based water-soluble self-decomposition environment-friendly grinding material and preparation method thereof

Abstract

The invention belongs to the technical field of industrial abrasives, and particularly relates to a sodium bicarbonate-based water-soluble self-decomposition environment-friendly abrasive and a preparation method thereof, which are suitable for precision machining, surface treatment and environment-friendly cleaning scenes. The hardness is improved by introducing a nano reinforced phase to meet the medium-load grinding requirement, a hydrophobic coating is formed by adopting a supercritical fluid coating technology to inhibit deliquescence, a core-shell structure is designed to realize repeated utilization of the grinding material and reduce the cost, meanwhile, a low-temperature solution method green preparation process is developed to reduce the energy consumption, and the balance among environmental protection, safety and processing efficiency is realized; and an innovative path is provided for green transformation of the abrasive industry.

Description

Technical Field

[0001] The present invention belongs to the technical field of industrial abrasives, and specifically relates to a sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive and a preparation method thereof, which is suitable for precision machining, surface treatment and environmentally friendly cleaning scenarios. Background Art

[0002] In the field of industrial processing, abrasives are widely used as core consumables in mechanical processing, semiconductor manufacturing and other scenarios. The current mainstream abrasives include traditional inorganic abrasives represented by aluminum oxide and silicon carbide, organic abrasives represented by resin base and rubber base, as well as environmentally friendly abrasives such as bio-based and mineral-based.

[0003] Although traditional inorganic abrasives have high hardness and strong wear resistance, their chemical properties are stable and difficult to degrade naturally, and they are easily prone to soil and water pollution after being discarded; organic abrasives are flexible but have poor high temperature resistance and may release volatile harmful substances that threaten health; environmentally friendly abrasives such as garnet do not have free silicon and can be recycled, but their hardness is insufficient to meet high-precision processing requirements.

[0004] Existing technologies generally face challenges with environmental impact due to their non-degradability, occupational health risks caused by dust, high disposal costs and resource waste, as well as substrate damage caused by hard abrasives and low efficiency due to flexible abrasives. Sodium bicarbonate, an environmentally friendly inorganic compound, decomposes into harmless substances such as water and carbon dioxide upon contact with water or high temperatures, while its weak alkalinity provides surface cleaning and micro-blasting effects. This offers a new approach to addressing these issues. By combining sodium bicarbonate with an elastic substrate to form a flexible abrasive, it can also improve adhesion and reduce damage during precision device processing.

[0005] However, the existing sodium bicarbonate-based abrasive has a Mohs hardness of only 2, resulting in a low material removal rate. It is easily deliquesced in high temperature and high humidity environments, affecting its stability. In addition, the preparation process is complex and the production cost is high. Currently, it is mainly limited to the field of industrial cleaning and its application in precision machining is limited. Summary of the Invention

[0006] In response to the bottlenecks of the existing technology, the present invention proposes a sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive and a preparation method thereof. By introducing a nano-reinforced phase to increase the hardness to meet the medium-load grinding requirements, supercritical fluid coating technology is used to form a hydrophobic coating to inhibit deliquescence, a core-shell structure is designed to achieve abrasive reuse and reduce costs, and a low-temperature solution method green preparation process is developed to reduce energy consumption, achieving a balance between environmental protection, safety and processing efficiency, and providing an innovative path for the green transformation of the abrasive industry.

[0007] The technical solution of the present invention is: A sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive comprises the following components in percentage by mass: Sodium bicarbonate 85-90%; 3-8% of a nano-reinforced phase, wherein the nano-reinforced phase is selected from one or more of graphene and titanium dioxide; 3-5% of elastic substrate, wherein the elastic substrate is selected from one or more of polyurethane and silicone rubber; Micron-grade iron-based magnetic powder 1-5%; The abrasive is designed with a core-shell structure, with an elastic substrate as the core, the iron-based magnetic powder embedded in the core, and a composite shell composed of sodium bicarbonate and a nano-reinforced phase wrapped around the core.

[0008] Furthermore, the surface of the sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive is coated with a hydrophobic silica coating formed by supercritical CO2 fluid, and the coating thickness is 50-100 nm.

[0009] Furthermore, the above-mentioned sodium bicarbonate-based water-soluble self-degradable environmentally friendly abrasive has a deliquescence time of ≥120 hours under an environment of 70° C. and 80% humidity.

[0010] Furthermore, in the above-mentioned sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive, the thickness ratio of the core-shell structure is (1-3):1.

[0011] Furthermore, in the above-mentioned sodium bicarbonate-based water-soluble self-decomposable environmentally friendly abrasive, the particle size of the nano-reinforced phase is 10-50 nm, and the particle size of the elastic base material is 50-200 μm. The method for preparing the above-mentioned sodium bicarbonate-based water-soluble self-degradable environmentally friendly abrasive comprises the following steps: (1) Raw material pretreatment: Dry the sodium bicarbonate powder at 50-60°C for 2-3 hours; (2) Raw material mixing: Add sodium bicarbonate, nano-reinforced phase, elastic matrix and micron-sized iron-based magnetic powder into deionized water at 30-50°C according to the proportion, and ultrasonically disperse for 30-40 minutes; (3) Abrasive forming: The mixed solution is spray-dried with a hot air flow temperature of 75-80°C to form core-shell structure particles; (4) Supercritical coating treatment: Use supercritical CO2 fluid to form a hydrophobic silica coating on the particle surface.

[0012] Furthermore, in the preparation method of the above-mentioned sodium bicarbonate-based water-soluble self-decomposable environmentally friendly abrasive, the pressure of the supercritical CO2 fluid is 10-15 MPa, the temperature is 35-45°C, and the coating time is 1-2 hours.

[0013] Furthermore, in the above-mentioned method for preparing the sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive, the energy consumption in the supercritical coating treatment is reduced by 35% compared with the traditional high-temperature process, and no acid or alkali waste liquid is discharged during the preparation process.

[0014] Advantages and beneficial effects of the present invention: 1. The present invention significantly improves the comprehensive performance of sodium bicarbonate-based abrasives through the collaborative innovation of material modification and structural design. In terms of material composition, the introduction of reinforcing phases such as nano-graphene increases the hardness of the abrasive from the Mohs hardness of 2 of traditional sodium bicarbonate to Mohs 4-5. While retaining its weak alkaline cleaning ability and self-decomposition properties, it can meet the material removal efficiency requirements of medium-load grinding scenarios such as metal surface rust removal and plastic substrate polishing. The entire chain from raw materials to preparation to application is green and environmentally friendly, promoting the development of the abrasive industry towards high efficiency, safety and sustainability.

[0015] 2. Reduced damage to the substrate, the abrasive adhesion in curved surface processing reaches more than 95%.

[0016] 3. Reduce the roughness of the substrate surface. When grinding aircraft engine blades, the surface roughness Ra value is reduced from 3.2μm to 0.8μm.

[0017] 4. Improved the utilization rate of abrasives, achieved 80% recycling rate of abrasives, and reduced energy consumption by 35% compared with traditional processes. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Schematic diagram of the core-shell structure of the abrasive in Example 1 of the present invention. DETAILED DESCRIPTION

[0019] The present invention discloses a sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive, which uses food-grade sodium bicarbonate as the core raw material and innovatively introduces nano-graphene and titanium dioxide reinforcement phases. While retaining its water-soluble self-decomposing and environmentally friendly characteristics, the abrasive hardness is increased from 2-2.5 Mohs hardness to 4-5, solving the problem of insufficient performance of traditional environmentally friendly abrasives; an "elastic core-composite shell" structure is designed, and the elastic base material core is embedded with magnetic powder to achieve 95% surface fit and 80% magnetic separation recovery rate, taking into account both processing accuracy and efficiency; a low-temperature solution dispersion-supercritical fluid coating green process is developed, which reduces energy consumption by 35% compared with the traditional process, and the surface hydrophobic coating extends the deliquescence time by 5 times, eliminating the hidden dangers of storage stability; a full life cycle system is constructed from environmentally friendly raw materials, green processes to recycling cycles, decomposition products are harmlessly discharged, and waste abrasives can be regenerated by high-temperature calcination, achieving a deep unity of "high performance" and "sustainability", providing a demonstration plan for material-structure-process collaborative innovation in the field of industrial grinding.

[0020] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention. Example 1

[0021] This embodiment provides a sodium bicarbonate-based water-soluble self-degrading environmentally friendly abrasive, comprising the following components in percentage by mass: Sodium bicarbonate 90%, nano titanium dioxide 5%, polyurethane elastic prepolymer 3%, micron-grade iron-based magnetic powder 2%; The particle size of the nano-titanium dioxide is 10 nm, and the particle size of the polyurethane elastic prepolymer is 50 μm; Among them, Figure 1 As shown, the abrasive is designed with a core-shell structure, with an elastic substrate as the core, the iron-based magnetic powder embedded in the core, and a composite shell composed of sodium bicarbonate and a nano-reinforced phase wrapped outside the core, and the thickness ratio of the core-shell structure is 1:3.

[0022] The surface of the abrasive is coated with a hydrophobic silicon dioxide coating formed by supercritical CO2 fluid, and the coating thickness is 50nm.

[0023] The preparation method of the abrasive comprises the following steps: 1) Prepare 99.6% pure sodium bicarbonate powder, nano-titanium dioxide powder, and polyurethane elastomer prepolymer. Dry the sodium bicarbonate powder at 60°C for 2 hours to remove moisture. 2) Sodium bicarbonate powder, nano-titanium dioxide powder, polyurethane elastomer prepolymer, and micron-sized iron-based magnetic powder were added to a 30°C deionized water solution according to mass percentage and ultrasonically dispersed for 40 minutes to uniformly disperse the nano-titanium dioxide. 3) The mixed solution is passed through a spray dryer and dried in a hot air flow at 80°C to form abrasive particles with a core-shell structure; 4) A hydrophobic silica coating is formed on the surface of the abrasive particles by supercritical CO2 fluid coating technology. The pressure of the supercritical CO2 fluid is 10 MPa, the temperature is 35°C, and the coating time is 1 hour.

[0024] Testing of abrasives: Hardness test: Using a Mohs hardness tester, the hardness was measured to be 4.5, which meets the requirements of medium-load grinding.

[0025] Deliquescence time test: Under the environment of 70℃ and 80% humidity, the deliquescence time is 120 hours, with excellent stability.

[0026] Recycling rate test: Through magnetic separation recovery, the utilization rate reaches 82%, which significantly reduces costs. Example 2

[0027] This embodiment provides a sodium bicarbonate-based water-soluble self-degrading environmentally friendly abrasive, comprising the following components in percentage by mass: Sodium bicarbonate 85%, graphene nanosheets 8%, silicone rubber precursor solution 5%, micron-sized iron-based magnetic powder 2%; The particle size of the graphene nanosheets is 50 nm; The abrasive is designed with a core-shell structure, with an elastic substrate as the core, the iron-based magnetic powder embedded in the core, and a composite shell composed of sodium bicarbonate and a nano-reinforced phase wrapped outside the core. The thickness ratio of the core-shell structure is 3:1.

[0028] The surface of the abrasive is coated with a hydrophobic silicon dioxide coating formed by supercritical CO2 fluid, and the coating thickness is 100 nm.

[0029] The preparation method of the abrasive comprises the following steps: 1) Prepare 99.5% pure sodium bicarbonate powder, graphene nanosheets, and silicone rubber precursor solution. Dry the sodium bicarbonate powder at 50°C for 3 hours to remove moisture. 2) Sodium bicarbonate powder, graphene nanosheets, silicone rubber precursor solution, and micron-sized iron-based magnetic powder were added to a deionized water solution at 40°C according to mass percentage and ultrasonically dispersed for 35 minutes; 3) The mixed solution is passed through a spray dryer and dried in a hot air flow at 75°C to form abrasive particles with a core-shell structure; 4) A hydrophobic silica coating is formed on the surface of the abrasive particles by supercritical CO2 fluid coating technology, wherein the pressure of the supercritical CO2 fluid is 15 MPa, the temperature is 45°C, and the coating time is 2 hours.

[0030] Testing of abrasives: Hardness test: Using a Mohs hardness tester, the hardness was measured to be 4.8, which is an excellent hardness performance.

[0031] Deliquescence time test: At 70°C and 80% humidity, the deliquescence time is 128 hours, indicating excellent storage stability.

[0032] Recycling rate detection: Through magnetic separation recovery, the utilization rate reaches 80%, achieving efficient recycling.

[0033] Comparative Example: This comparative example is a sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive, and the preparation method is as follows: 1) Basic treatment: Prepare 99.5% pure sodium bicarbonate powder and ordinary aluminum oxide abrasive particles. Dry the sodium bicarbonate powder at 60°C for 2 hours. 2) Raw material mixing: 70% sodium bicarbonate, 25% ordinary aluminum oxide abrasive, and 5% auxiliary additive (dispersant) were mixed in a 30°C deionized water solution with stirring for 20 minutes. Ultrasonic dispersion treatment was not used. 3) Abrasive forming: The mixed solution is directly dried without spray drying and supercritical CO2 fluid coating treatment to form ordinary powdered abrasive.

[0034] 4) Test content: Hardness test: Using a Mohs hardness tester, the hardness was measured to be 3.2. Insufficient hardness resulted in low grinding efficiency.

[0035] Deliquescence time test: Under the environment of 70℃ and 80% humidity, deliquescence and agglomeration will occur within 24 hours and it cannot be used any further.

[0036] Recycling rate test: Since the abrasive has no magnetic separation characteristics and a loose structure, mechanical screening recovery was attempted, but the utilization rate was only 15%, with high recycling costs and poor results.

[0037] By comparison with Examples 1 and 2, the traditional abrasive in the comparative example is significantly lower in hardness, stability and recycling rate than the flexible composite abrasive of the present invention due to the lack of elastic buffer, self-cleaning components and special molding process, which verifies the outstanding advantages of the technical solution of the present invention in performance optimization.

[0038] The above embodiments are intended only to illustrate the technical concepts and features of the present invention and to enable those skilled in the art to understand and implement the present invention accordingly. They are not intended to limit the scope of protection of the present invention. Any changes and modifications made without violating the spirit and substance of the present invention are intended to be included within the scope of protection of the claims of the present invention.

Claims

1. A sodium bicarbonate-based water-soluble self-decomposable environmentally friendly abrasive, characterized in that: The following components are included in mass percentage: Sodium bicarbonate 85-90%; 3-8% of a nano-reinforced phase, wherein the nano-reinforced phase is selected from one or more of graphene and titanium dioxide; 3-5% of elastic substrate, wherein the elastic substrate is selected from one or more of polyurethane and silicone rubber; Micron-grade iron-based magnetic powder 1-5%; The abrasive is designed with a core-shell structure, with an elastic substrate as the core, the iron-based magnetic powder embedded in the core, and a composite shell composed of sodium bicarbonate and a nano-reinforced phase wrapped around the core.

2. A sodium bicarbonate-based water-soluble self-degradable environmentally friendly abrasive according to claim 1, characterized in that: The surface of the abrasive is coated with a hydrophobic silicon dioxide coating formed by supercritical CO2 fluid, and the coating thickness is 50-100 nm.

3. A sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive according to claim 2, characterized in that: The abrasive has a deliquescence time of ≥120 hours under an environment of 70° C. and 80% humidity.

4. The sodium bicarbonate-based water-soluble self-degradable environmentally friendly abrasive according to claim 1, characterized in that: The thickness ratio of the core-shell structure is (1-3):

1.

5. The sodium bicarbonate-based water-soluble self-decomposing environmentally friendly abrasive according to claim 1, characterized in that: The particle size of the nano-reinforced phase is 10-50 nm, and the particle size of the elastic base material is 50-200 μm.

6. A method for preparing the sodium bicarbonate-based water-soluble self-degradable environmentally friendly abrasive according to any one of claims 1 to 5, characterized in that: The following steps are involved: (1) Raw material pretreatment: Dry the sodium bicarbonate powder at 50-60°C for 2-3 hours; (2) Raw material mixing: Add sodium bicarbonate, nano-reinforced phase, elastic matrix and micron-sized iron-based magnetic powder into deionized water at 30-50°C according to the proportion, and ultrasonically disperse for 30-40 minutes; (3) Abrasive forming: The mixed solution is spray-dried with a hot air flow temperature of 75-80°C to form core-shell structure particles; (4) Supercritical coating treatment: Use supercritical CO2 fluid to form a hydrophobic silica coating on the particle surface.

7. The method for preparing the sodium bicarbonate-based water-soluble self-decomposable environmentally friendly abrasive according to claim 5, characterized in that: The pressure of the supercritical CO2 fluid is 10-15 MPa, the temperature is 35-45°C, and the coating time is 1-2 hours.

8. The method for preparing the sodium bicarbonate-based water-soluble self-decomposable environmentally friendly abrasive according to claim 5, characterized in that: The energy consumption in the supercritical coating process is reduced by 35% compared with the traditional high-temperature process, and no acid or alkali waste liquid is discharged during the preparation process.

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