A new ceramic abrasive and a preparation method of dry sand paper thereof

Abstract

This invention relates to the field of precision grinding materials and grinding wheels, specifically to a novel ceramic abrasive and its preparation method for dry sandpaper. This invention achieves improvements in various aspects of the abrasive material's performance through innovative optimization of added materials and key process conditions in the abrasive preparation system. Specifically, it includes adding composite seed crystals and composite additives to the novel ceramic abrasive preparation formula. The novel ceramic abrasive employs a two-step staged heat-holding sintering method during the sintering stage, thereby enhancing the grinding efficiency of the grinding wheel, reducing the abrasive loss rate, and effectively preventing abnormal heating and decreased grinding efficiency caused by abrasive falling and clogging during grinding wheel use.

Description

Technical Field

[0001] This invention relates to the field of new materials for precision grinding and grinding tools, specifically to a novel ceramic abrasive and a method for preparing its dry sandpaper. Background Technology

[0002] Grinding is a crucial processing method in cold working of materials, typically used for finishing or semi-finishing. Its application in the preparation of high-end grinding tools is therefore significant. Abrasives for grinding tools are categorized into natural and synthetic abrasives, and further classified by hardness into ordinary and superhard abrasives. Ceramic corundum, as one of the most promising emerging abrasives, has significant research value in its preparation methods.

[0003] There are various methods for preparing ceramic corundum, including sol-gel method, chemical coprecipitation method, hydrothermal method, powder sintering method, solid-phase thermal decomposition method, self-propagating high-temperature synthesis method, and corundum abrasive encapsulation method, etc. Among them, the sol-gel method has a better overall preparation effect. It uses liquid chemical reagents (or powdered reagents dissolved in liquid solvent) or sol as raw materials, instead of traditional powdered materials. The reactants are uniformly mixed and reacted in the liquid phase, and the reaction product is a stable sol system. After standing for a period of time, it transforms into a gel. The liquid medium is evaporated to remove the gel, and then the gel is dried. The dried gel precursor is calcined to remove organic components and bound water, and finally the desired product is obtained.

[0004] Currently reported patents related to the preparation of precision grinding materials and grinding wheels include those that improve the material system and those that optimize the preparation process by changing the parameters. The optimization directions are mostly focused on optimizing specific parameters and adding new reagents or materials. For example, Chinese patent CN112171530A discloses a ceramic-corundum abrasive coated grinding wheel and its preparation method. The ceramic-corundum abrasive coated grinding wheel includes a substrate layer and a working layer. The working layer includes a primer layer, an abrasive embedded in the primer layer, and a topcoat layer coated on the abrasive and the primer. The abrasive is characterized by being an ion-implanted ceramic-corundum abrasive. The aforementioned ceramic corundum abrasive coated abrasives do not require alteration of the abrasive's internal properties. Surface modification is achieved through ion implantation, synergistically enhancing surface hardening, strengthening, and toughening. This makes the abrasive less prone to breakage and detachment from the base coat, and it can break under heavy loads, improving its self-sharpening ability and significantly enhancing surface properties. This results in improved overall abrasive performance, allowing the coated abrasives to meet the performance requirements of precision high-speed, heavy-duty grinding and polishing while maintaining a long service life. Chinese patent CN116789459A discloses a ceramic corundum abrasive, its preparation method, and applications. Using industrial-grade boehmite as raw material, a double-electron-layer structure of boehmite particles is formed by adding the adhesive HNO3, preparing a boehmite sol. The finished abrasive is then prepared through sol-gel, crushing, grading, and sintering processes. Specific modifying components are introduced during sol preparation and sintering to promote sol-gel and product performance improvements, while also increasing production efficiency, demonstrating significant market value.

[0005] In summary, existing inventions in the preparation of ceramic corundum abrasives and grinding tools often focus on optimizing certain key parameters or introducing certain modified auxiliary materials, but none of them consider the materials and process conditions of the preparation system to achieve a significant improvement in the performance of ceramic corundum materials. Summary of the Invention

[0006] Based on the problems summarized above, this invention provides a novel ceramic abrasive and its dry sandpaper preparation method. Its main feature is the innovative optimization of materials added to the abrasive preparation system and the optimization of key process conditions, enabling the ceramic corundum abrasive to achieve a high performance level during abrasive formation. The resulting abrasive tool exhibits significantly improved grinding efficiency and abrasive retention. The specific technical solution is as follows:

[0007] A novel method for preparing ceramic abrasives, wherein the formulation of the novel ceramic abrasives includes composite seed crystals and composite additives, and the novel ceramic abrasives employ a two-step sintering process in the sintering stage.

[0008] The preparation method of the novel ceramic abrasive includes the following steps:

[0009] Step 1: Prepare composite seed crystals. Use alumina hydrate as the main raw material to make a gel. Then introduce a composite additive consisting of metal oxide and SiO2 into the aged gel to form a mixture. After ball milling and drying, the mixture is crushed and graded. Select particles of a certain mesh size for sintering to obtain composite seed crystals.

[0010] Step 2: Prepare abrasive gel using alumina hydrate as the main raw material, add dispersant to prepare a suspension, stir thoroughly in a water bath, add acid to adjust the pH to an appropriate range, repeat water bath stirring, and then age at room temperature.

[0011] Step 3: Prepare abrasive precursor. After washing the gel obtained in step 2 with deionized water, add a composite additive composed of metal oxide and SiO2, and then add the composite seed crystal prepared in step 1. Ball mill the mixture and then dry it.

[0012] Step 4: Abrasive sintering. The abrasive precursor obtained in step 3 is crushed and placed into a sintering furnace for atmospheric pressure sintering. Sintering is divided into two stages: rapid heating and fixed temperature holding.

[0013] The composite seed crystal mentioned in step one is a composite secondary seed crystal;

[0014] The alumina hydrate mentioned in step one is at least one of boehmite, aluminum hydroxide, boehmite or boehmite monohydrate;

[0015] The metal oxides mentioned in step one are MgO, CaO and α-Al2O3, wherein the amount of MgO-CaO-SiO2 added is 2.5 wt.%, the molar ratio is 5:1:5, and the amount of α-Al2O3 added is 3.0 wt.%.

[0016] The particles with a certain mesh size mentioned in step one are between 60 and 120 mesh.

[0017] The alumina hydrate mentioned in step two is at least one of boehmite, aluminum hydroxide, boehmite or boehmite monohydrate.

[0018] The dispersant mentioned in step two is at least one of ammonium citrate, ammonium polyacrylate, or PEG;

[0019] The pH-adjusting acid mentioned in step two is HNO3. 3、 Citric acid 、 Hydrochloric acid (at least one of the following);

[0020] The appropriate pH range described in step two is 2-3.

[0021] The metal oxides mentioned in step three are MgO and TiO2, and the amount of MgO-TiO2-SiO2 added is 2.0 wt.%, with a molar ratio of 3:5:11;

[0022] The amount of composite seed crystals prepared in step one, as described in step three, is 2.0 wt.% - 3.5 wt.%.

[0023] Preferably, the amount of composite seed crystals added is 2.5 wt.%.

[0024] The rapid heating rate described in step four is 5℃ / min, and the final temperature after heating is 1350℃.

[0025] Step four describes a fixed-temperature insulation stage, which includes a first stage and a second stage.

[0026] The first stage of the heat preservation process involves a heat preservation temperature of 1050℃-1250℃ and a heat preservation time of 1 hour. The second stage involves a heat preservation temperature of 950℃ and a heat preservation time of 4 hours.

[0027] Preferably, the insulation temperature in the first stage of the insulation process is 1150℃.

[0028] A method for preparing a novel ceramic abrasive dry sandpaper includes the following steps: substrate treatment → applying a base coat → sanding → pre-drying → applying a top coat → applying an anti-clogging coating → drying → winding → re-wetting → storage → finished product.

[0029] The substrate is made of a composite substrate of flexible latex paper and PET film, and the substrate processing steps include substrate flexibility testing and surface smoothing treatment.

[0030] The adhesive used in the base coat is a flexible resin;

[0031] The sand planting process adopts a low-density sand planting process. In the sand planting step, the new ceramic abrasive is classified and screened to select the first 1 / 3 to 1 / 2 of the particle size and mix it with ordinary abrasive in a ratio of 30% to 50%.

[0032] The composite adhesive contains thermosetting methyl phenolic resin, NBR, acrylic emulsion, and an antistatic agent.

[0033] Compared with the prior art, the present invention has the following beneficial effects:

[0034] (1) In the preparation of new abrasive materials, the present invention adds composite secondary seed crystals, which can effectively guide the formation of homogeneous grains below 100 nanometers. It can induce the rapid formation of a large number of tiny homogeneous grains in the early stage of rapid heating during sintering, thereby accelerating the densification of the entire system and ensuring the improvement of the performance of the final abrasive material in all aspects.

[0035] (2) The present invention adopts a two-step staged heat preservation sintering method in the sintering stage of the new material abrasive. Combined with the previous composite secondary seed crystal and composite additive, it can provide appropriate energy intensity to the system at different stages of sintering, which can drive the densification and growth of grains without causing the grain arrangement and morphology to be distorted, thus ensuring the performance of the new abrasive material in all aspects.

[0036] (3) In the grinding wheel preparation and testing stage, the present invention adopts low-density sand planting, adding antistatic agent and adding anti-clogging coating and other process methods to improve the grinding efficiency of the grinding wheel and reduce the abrasive loss rate. Combined with the excellent fracture toughness of the new abrasive material itself, it effectively prevents the abnormal heating and grinding efficiency reduction caused by excessive abrasive falling and clogging during the use of the grinding wheel. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating the preparation process of the novel ceramic abrasive of the present invention.

[0038] Figure 2 Line graphs showing the comparison of single-particle compressive strength and relative density of abrasive samples from Examples 1-4 and Comparative Example 1;

[0039] Figure 3 Line graphs showing the comparison of hardness and fracture toughness of the abrasive samples from Examples 1-4 and Comparative Example 1;

[0040] Figure 4 Microstructure diagram of ceramic corundum small grains in the additive system used for preparing composite secondary seed crystals;

[0041] Figure 5 Comparative diagrams of the microstructures of the novel ceramic abrasives prepared in Comparative Example 1 (left) and Example 2 (right);

[0042] Figure 6 Line graphs showing the comparison of single-particle compressive strength and relative density of abrasive samples from Examples 2, 5, 6 and Comparative Example 2;

[0043] Figure 7 Line graphs showing the comparison of hardness and fracture toughness of abrasive samples from Examples 2, 5, 6, and Comparative Example 2. Detailed Implementation

[0044] The following embodiments further explain and illustrate the technical solutions of the present invention. It should be specifically noted that each specific embodiment is a concretization and explanation of the technical solution and should not be considered as a limitation on the scope of protection of the present invention. Those skilled in the art still have the right to modify the technical solutions of these embodiments and make equivalent substitutions for some or all of the technical features, and these modifications or substitutions do not change the essence of the corresponding technical solutions, nor do they cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions described in the present invention.

[0045] The reagents and instruments used in the embodiments can be purchased from the market, and the detection methods adopt conventional methods well known in the art. Based on the technical requirements of precision grinding, the detection mainly focuses on the single-particle compressive strength, relative density, hardness, fracture toughness, microstructure and grinding performance of the new ceramic abrasive and the molded grinding wheel samples.

[0046] 1. Single-particle compressive strength test:

[0047] The compressive strength of a single particle of ceramic corundum abrasive was tested using a diamond hydrostatic compressive strength tester, according to JB / T7988.1-1999 "Method for Determination of Compressive Strength of Synthetic Diamond or Cubic Boron Nitride". Compressive strength refers to the load value of a single abrasive particle when it breaks under static pressure, expressed in Newtons (N). 1.5g of abrasive was taken and evenly distributed on a carrier plate. After scraping it into a straight line, 40 particles were sequentially picked up from the carrier plate and subjected to the breaking load for each particle. The arithmetic mean of these values ​​was taken as the compressive strength of a single particle at that particle size. All abrasive particles measured in the experiment were between 60 and 80 mesh.

[0048] 2. Relative density test:

[0049] The Archimedes displacement method is used to test the density of materials. Before measuring the density, the abrasive particles are dried at 110°C to constant weight, cooled to room temperature in a desiccator, and weighed. The mass of the abrasive particles is recorded as m (the abrasive being measured is generally no less than 1 / 3 and no more than 1 / 2 of the volume of the specific gravity bottle). The abrasive is poured into the specific gravity bottle, and a vacuum is applied for 5 minutes. Distilled water is then poured in to submerge the abrasive, and the vacuum is continued for 15 minutes. The specific gravity bottle is then filled with distilled water, and the mass of the specific gravity bottle containing the abrasive and filled with distilled water is recorded as m2. The abrasive and distilled water in the specific gravity bottle are then discarded and the bottle is cleaned. It is then refilled with distilled water, and the mass of the specific gravity bottle filled with distilled water is measured as m1. The density of the abrasive is calculated using the following formula:

[0050]

[0051] In the formula ρ s The effective density of the abrasive particles is expressed in g·cm³. -3 ρ is the density of distilled water at the measurement temperature, in g·cm³. -3 m is the mass of the abrasive, g; m1 is the mass of the specific gravity bottle filled with water, g; m2 is the mass of the specific gravity bottle containing the abrasive and filled with water, g.

[0052] 3. Hardness test:

[0053] The hardness value of the material was measured using a Vickers microhardness tester. Before testing, the sample surface was polished to a mirror finish. The load was 5 kg. The test result was the average of five hardness values ​​from different locations on the same sample. The Vickers hardness H...V The calculation formula is as follows:

[0054]

[0055] In the formula, Hv is the Vickers hardness, MPa; P is the applied load, N; and d is the average length of the diagonal of the indentation, mm.

[0056] 4. Toughness test:

[0057] Fracture toughness was calculated using the Vicker indentation method, and the formula is as follows:

[0058]

[0059] In the formula K IC The fracture toughness of the sample is given by MPa·cm. 1 / 2 E is the Young's modulus of alumina, in GPa; H v ρ is Vickers hardness, MPa; P is the applied load, N; c is the average crack length, mm.

[0060] 5. Microstructure observation

[0061] The microstructure of the abrasive sample surface was analyzed using field emission scanning electron microscopy. The grain size was measured using the linear intercept method, as shown in the following formula:

[0062]

[0063] In the formula The average grain size is 1.56, the correction factor is C, the length of the cut-off segment is N, the number of cut-off points is M, and the magnification of the photograph is M.

[0064] 6. Grinding performance test

[0065] Referring to JBT 10155-2012 "Test Method for Grinding Performance of Coated Abrasives, Abrasive Cloth, and Abrasive Paper" and based on actual testing requirements, abrasive samples were prepared as circular specimens with an outer diameter of 165mm ± 2mm and an inner diameter of 10-20mm. These were then tested using a grinding performance testing instrument. Parameter settings: grinding disc end face runout no greater than 0.05mm; grinding disc rotation speed (320 ± 5) r / min; grinding trajectory circular with an inner diameter of 87 ± 0.2mm and a ring width of 16.5 ± 0.4mm; grinding pressure constant at 15N. (Dry grinding, abrasive sample mesh size fixed at 120).

[0066] Test Procedure: After placing the sample under atmospheric conditions for 24 hours, weigh it and place it on the grinding disc of the grinding performance tester. After maintaining a constant grinding pressure, start the test and time for 30 minutes. Then, weigh the mass of the sample rod (aluminum rod) and the sample itself. The amount of metal removed and the amount of sand removed from the sample are calculated by the mass difference before and after grinding.

[0067] Example 1

[0068] A novel method for preparing ceramic abrasives is as follows:

[0069] (1) Preparation of composite secondary seed crystals: Boehmite was used as the main raw material to prepare gel. After aging, composite additives MgO-CaO-SiO2 (2.5wt.%, molar ratio 5:1:5) and α-Al2O3 (3.0wt.%) were introduced. The mixture was ball-milled for 2 hours with anhydrous alcohol as the medium (speed set at 250 r / min). After drying (80℃, 15h), it was crushed and classified. Particles between 80 and 100 mesh were selected for atmospheric pressure sintering (the temperature was rapidly increased to 1350℃ at a rate of 5℃ / min and then reduced to 1150℃ and held for 5h). After sintering, composite secondary seed crystals were obtained for later use.

[0070] (2) Preparation of abrasive gel: Boehmite was used as the main material, and PEG1000 (1wt.%) was added to prepare a suspension with a solid content of 35%. After stirring thoroughly in a water bath at 60℃ for 15 min, 1 mol / L HNO3 was added to adjust the pH of the system to 2.5-2.8. After repeated stirring in the water bath for 1 h, the system was aged at room temperature for 24 h.

[0071] (3) Preparation of abrasive precursor: The aged gel was washed three times with deionized water, and the composite additive MgO-TiO2-SiO2 (2.0 wt.%, molar ratio 3:5:11) and composite secondary seed crystal (2.0 wt.%) were introduced. The gel was ball-milled for 2 h with anhydrous alcohol as the medium (speed set at 250 r / min). The resulting slurry was then dried (80℃, 15 h).

[0072] (4) Abrasive sintering: The dried block material is crushed and placed in a sintering furnace for atmospheric pressure sintering. During sintering, a two-step stage heat preservation sintering is adopted. In the initial stage of sintering, the temperature is rapidly increased to 1350℃ at 5℃ / min, then the sintering temperature is reduced to 1050℃ and kept for 1 hour, and then the temperature is reduced to 950℃ and kept for 4 hours.

[0073] Examples 2-4

[0074] A novel method for preparing ceramic abrasives is described. The preparation process is basically the same as in Example 1, except that the amount of composite secondary seed crystals added in step three, the preparation of the abrasive precursor, is 2.5 wt.%, 3.0 wt.%, and 3.5 wt.%, respectively.

[0075] Comparative Example 1

[0076] A novel method for preparing ceramic abrasives is described. The preparation process is basically the same as in Example 1, except that there is no preparation of composite secondary seed crystals. In step three, the seed crystal material added in the preparation of the abrasive precursor is α-Al2O3 (3.0 wt.%).

[0077] The abrasives obtained in Examples 1-4 and Comparative Example 1 were tested for several performance parameters, including single-particle compressive strength, relative density, hardness, and fracture toughness. The results are shown in the appendix. Figure 2 Appendix Figure 3 And as shown in Table 1:

[0078] Table 1 Comparison of various properties of the abrasives obtained in Examples 1-4 and Comparative Example 1

[0079]

[0080] Based on the above test results, it can be seen that Comparative Example 1, which added conventional seed crystals, lags behind all examples in terms of abrasive performance in all aspects. The main reasons are as follows: ① The MgO-CaO-SiO2 multiphase additive is a classic ceramic corundum small-grain auxiliary additive system, which can effectively guide the formation of homogeneous grains smaller than 100 nanometers (from the attached...). Figure 4 It can be seen that by pre-preparing homogeneous small grains as seed crystals and introducing them into the subsequent abrasive preparation process, the α-Al2O3 phase transformation temperature can be effectively reduced. Furthermore, the homogeneous small grains themselves act as nucleation guides, inducing the subsequent abrasive to form a dense, fine grain morphology. Although adding a single α-Al2O3 seed crystal can achieve a similar effect, the effect of composite secondary seed crystals is stronger and more effective. Compared with single α-Al2O3 seed crystals, MgO, CaO, and SiO2 can significantly inhibit the abnormal growth of alumina grains and easily form micro-liquid phases at grain boundaries to accelerate densification during sintering. ② Although additives from the MgO-TiO2-SiO2 system are added in addition to the additive components carried by the seed crystals during subsequent preparation, the two systems differ significantly in their effects on grain formation and growth, besides their different compositions. It is precisely through the introduction of secondary seed crystals that the influence of different additive systems can be controlled relatively easily and accurately during the preparation process. If MgO, CaO, and SiO2 are used... 2、Directly adding TiO2 as an additive in the same system will greatly increase the complexity of the system reaction. Optimizing the amount and molar ratio of this additive system will be a very complex and difficult task to control. ③ The two additive systems mentioned above can avoid their respective adverse effects and give full play to their own beneficial effects by using different addition methods. In the early stage of rapid heating during sintering, due to the guidance of composite secondary crystal seeds and the influence of several additives such as MgO, CaO and SiO2, a large number of small homogeneous grains are rapidly formed, and the densification speed of the entire system is accelerated. Until the grain boundaries between grains become more obvious, sintering enters the heat preservation stage at a lower temperature. Under the influence of the MgO-TiO2-SiO2 additive system, the growth rate of a few alumina grains on different crystal planes is differentiated, and they grow rapidly in anisotropy with the help of a small number of gaps between grains, forming an interlocking grain structure between grains of different morphologies, making the entire system more compact. ④ The test results show that the lower fracture toughness of the comparative example is more pronounced compared to other performance parameters. This is because, without the guiding effect of the composite secondary seed crystal, the MgO-TiO2-SiO2 additive system alone can enhance the toughness of the abrasive to some extent. However, without the strong induction effect of the secondary seed crystal in the early stage, under the influence of subsequent additives, more alumina grains will grow anisotropically. In particular, some lamellar grains formed without induction constraint will grow rapidly in the thickness direction, increasing the intergranular gaps and failing to form a relatively dense grain interlocking structure. Figure 5 A direct comparison shows the differences in microstructure between Comparative Example 1 (left) and Example 2 (right).

[0081] Examples 5-6

[0082] A novel method for preparing ceramic abrasives is described. The preparation process is basically the same as that in Example 2, except that the first temperature reduction during sintering reaches 1150℃ and 1250℃ respectively.

[0083] Comparative Example 2

[0084] A novel method for preparing ceramic abrasives is described. The preparation process is basically the same as in Example 2, except that after sintering, the temperature is rapidly raised to 1350°C and then directly cooled to 950°C and held for 5 hours.

[0085] Based on the kinetics of the ceramic corundum abrasive (with additives) system under sintering conditions, the system can achieve a density greater than 75% at temperatures above 1250℃. Rapid densification can be achieved at around 1350℃ without excessive grain size increase. Therefore, the initial sintering temperature of this invention is fixed at 1350℃. Since the composite secondary seed system can reduce the minimum temperature required for grain boundary diffusion, the minimum holding temperature is fixed at 950℃. The experiment compared the intermediate temperatures during the first cooling phase; the results are shown in Table 2 and Appendix. Figure 6 and attached Figure 7 As shown:

[0086] Table 2 Comparison of various performance characteristics of abrasives obtained in Examples 2, 5, 6 and Comparative Example 2

[0087]

[0088]

[0089] Based on the above test results, it can be seen that setting the intermediate heat preservation temperature at 1150℃ can yield ceramic corundum abrasive with better overall performance. Although Comparative Example 2 achieved a comparable level in terms of single-particle compressive strength, relative density, and hardness, its fracture toughness was still much lower than that of Example 5. This is precisely the significance of setting the intermediate heat preservation step. The conventional two-step sintering method first heats the material to a high temperature to give the system a thermodynamic driving force sufficient for grain boundary diffusion, and then rapidly cools it to a lower temperature and continues to hold it, thereby inhibiting grain boundary migration and fully eliminating pores by utilizing the diffusion effect of grain boundaries, so that the material becomes dense. Its application in general ceramic corundum abrasive (with additives) systems can achieve good sintering results. However, the additive system established in this invention contains composite secondary seed crystals. During the initial heating and sintering, in addition to inducing the rapid generation of fine grains, the composite secondary seed crystals also form a continuous liquid phase that fills the spaces between grains. As a second phase at grain boundaries, it effectively inhibits abnormal grain growth. At this point, it is necessary to hold the temperature at a relatively high temperature for a period of time to provide energy for the anisotropic and continuous growth of a few alumina grains in the grain voids. In this way, a better grain system with interlocking different morphological structures will be formed in the final holding stage, further enhancing the overall apparent fracture toughness. However, as can be seen from Example 6, excessively high intermediate holding temperatures will overstimulate the growth of other grains, causing voids between grains, thereby reducing the overall structural density and leading to a decrease in performance.

[0090] Example 7

[0091] A novel method for preparing dry sandpaper using ceramic abrasives includes the following main process steps: substrate treatment → applying base adhesive → sanding → pre-drying → applying top adhesive → applying anti-clogging coating → drying → winding → re-wetting → storage → finished product.

[0092] The substrate is made of a composite substrate of flexible latex paper and PET film. The substrate processing steps include substrate flexibility testing and surface smoothing treatment. The binder of the base adhesive is a flexible resin such as epoxy resin and polyurethane resin. The abrasive used in the sand planting step is a mixture of the new material abrasive prepared in Example 5 and ordinary abrasive. The specific processing method is to classify the ceramic corundum abrasive, screen out the top 1 / 3 to 1 / 2 of the particle size, and mix it with ordinary abrasive at a ratio of 30% to 50%. The sand planting adopts a low-density sand planting process. The composite adhesive contains thermosetting methyl phenolic resin (solid content 60% to 80%), 5% to 20% NBR, acrylic emulsion, and 0.5% to 2% antistatic agent.

[0093] Comparative Example 3

[0094] A method for preparing a novel ceramic abrasive dry sandpaper is described. The main process flow and treatment process are the same as those in Example 7, except that the ceramic corundum abrasive used for sanding adopts the preparation material formula of Comparative Example 1.

[0095] Comparative Example 4

[0096] A method for preparing a novel ceramic abrasive dry sandpaper is described. The main process flow and treatment process are the same as those in Example 7, except that the ceramic corundum abrasive used for sanding adopts the sintering temperature scheme of Comparative Example 2.

[0097] Comparative Example 5

[0098] A method for preparing a novel ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as in Example 7, the difference being that the sand planting density is maintained at a normal density.

[0099] Comparative Example 6

[0100] A method for preparing a novel ceramic abrasive dry sandpaper is described. The main process flow and treatment process are the same as in Example 7, except that no antistatic agent is added during the adhesive coating.

[0101] Comparative Example 7

[0102] A method for preparing a novel ceramic abrasive dry sandpaper, the main process flow and treatment process are the same as in Example 7, the difference being that no anti-clogging coating is applied.

[0103] The grinding performance of the samples from Example 7 and Comparative Examples 3-7 was tested, and the results are shown in Table 3:

[0104]

[0105] In summary, the results show that Comparative Examples 3 and 4 suffer from lower abrasive properties due to differences in formulation and method during abrasive preparation, particularly lower fracture toughness, which negatively impacts grinding efficiency, material retention, and service life after grinding. Comparative Examples 5, 6, and 7 also experience a reduction in performance due to omissions in key grinding steps. While Comparative Example 5 exhibits a higher abrasive removal rate, the lack of low-density sand-coating technology increases the amount of sand removed, but the overall abrasive removal rate is not significantly improved. This demonstrates that low-density sand-coating reduces abrasive wear while maintaining a high abrasive removal rate. Comparative Examples 6 and 7 demonstrate the advantages of antistatic agents and anti-clogging coatings. Example 7, with its advantageous parameters, achieves high abrasive removal rate and low wear rate through improvements in abrasive and grinding tool preparation. The new abrasive material exhibits good self-sharpening properties, low wear rate, low heat generation, and high hardness, making it suitable for precision grinding applications. Furthermore, the low sand removal rate of the prepared grinding tool prevents process blockage, abnormal heating, and efficiency reduction.

Claims

1. A method for preparing ceramic abrasive, characterized in that, Includes the following steps: Step 1: Preparation of composite secondary seed crystals: A gel is prepared using at least one of boehmite, aluminum hydroxide, boehmite or diaspore as raw materials. After aging, 2.5 wt.% of MgO-CaO-SiO2 and 3.0 wt.% of α-Al2O3 are introduced, wherein the molar ratio of MgO-CaO-SiO2 is 5:1:

5. After ball milling, drying, crushing and classifying, 60-120 mesh particles are selected for sintering to obtain composite secondary seed crystals. Step 2: Preparation of abrasive gel: Using at least one of boehmite, aluminum hydroxide, boehmite or boehmite monohydrate as raw material, add at least one of ammonium citrate, ammonium polyacrylate or PEG to prepare a suspension. After stirring in a water bath at 60°C, add at least one of HNO3, citric acid or hydrochloric acid to adjust the pH to 2-3. Repeat stirring in a water bath and then age at room temperature. Step 3: Preparation of abrasive precursor: The gel from Step 2 was washed with deionized water, and 2.5 wt.% of MgO-TiO2-SiO2 and 2.5 wt.% of composite secondary seed crystals were added, with the molar ratio of MgO-TiO2-SiO2 being 3:5:

11. The mixture was then ball-milled and dried. Step 4, Abrasive Sintering: After crushing the abrasive precursor, place it into a sintering furnace and heat it to 1350℃ at a rate of 5℃ / min. Hold it at 1050℃-1250℃ for 1 hour, then cool it down to 950℃ and hold it for 4 hours. Sinter under normal pressure.

2. The method for preparing ceramic abrasive as described in claim 1, characterized in that, The first stage of the fixed temperature insulation phase in step four has a temperature of 1150℃.

3. A ceramic abrasive prepared by the preparation method as described in claim 1 or 2.

4. A method for preparing dry sandpaper using ceramic abrasive, characterized in that, The ceramic abrasive as described in claim 3 is prepared using the following steps: Substrate treatment: The substrate made of flexible latex paper and PET film is subjected to flexibility testing and surface smoothing treatment; Primer application: The primer adhesive is a flexible resin; Sand implantation: A low-density sand implantation process is adopted, in which ceramic abrasive is graded and the particles with the largest size of 1 / 3 to 1 / 2 are screened and mixed with ordinary abrasive at a ratio of 30% to 50% for implantation. After pre-drying, apply a topcoat: Add 60%-80% thermosetting methyl phenolic resin, 5%-20% NBR, acrylic emulsion and 0.5%-2% antistatic agent to the topcoat; Apply an anti-clogging coating, dry, roll up, rehumidify, and store to obtain the finished product.

5. A ceramic abrasive dry sandpaper prepared by the preparation method described in claim 4.

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