Diamond-based high-strength abrasive material and preparation method thereof

Abstract

The invention provides a high-strength grinding material based on diamond and a preparation method thereof. The grinding material comprises the following components in parts by weight: 40-70 parts of modified polyurethane, 10-20 parts of diamond, 10-25 parts of an auxiliary grinding material, 5-10 parts of modified aluminum oxide and 10-20 parts of mica powder. The grinding material disclosed by the invention has relatively high shore hardness which indicates that the grinding material is high in hardness, wide in application range, high in abrasion ratio, low in abrasion loss, good in abrasion resistance and relatively long in service life.

Description

Technical Field

[0001] The invention belongs to the technical field of abrasives, and in particular relates to a high-strength abrasive based on diamond and a preparation method thereof. Background Art

[0002] Abrasives refer to materials that play a cutting role in grinding, lapping and polishing. According to their sources, they can be divided into two categories: natural abrasives and artificial abrasives. According to their hardness, they can be divided into ordinary abrasives and superhard abrasives. They mainly include garnet, corundum, silicon carbide, diamond, cubic boron nitride, etc.

[0003] In order to meet the needs of grinding workpiece materials, abrasives generally need to have the following properties: (1) Hardness. Only when the hardness of the abrasive is higher than the hardness of the material to be processed can the purpose of grinding be achieved; (2) Toughness, that is, the ability to resist breakage when impacted. Too high or too low toughness is not conducive to grinding. If the toughness is too low, the abrasive will easily break during grinding. If the toughness is too high, the abrasive will become blunt, resulting in reduced grinding efficiency. Therefore, appropriate toughness strength is required to meet the processing performance of the abrasive; (3) Chemical stability. When the abrasive generates high temperature during grinding, certain chemical reactions may occur when it comes into contact with the workpiece. Therefore, the abrasive needs to have a certain chemical stability to ensure its grinding performance and the quality of the processed workpiece.

[0004] Diamond is a crystalline form of carbon and also an allotrope of carbon. It has the advantages of high hardness, good thermal conductivity, good chemical stability, wide semiconductor bandgap, and large full-wavelength light transmittance. Therefore, diamond is usually used as an abrasive in the prior art to achieve the required properties of the abrasive. Abrasives and grinding tools prepared using diamond have solved the problem of processing some high-hardness materials such as ceramics and glass. However, although the use of a large amount of diamond as the main abrasive can increase the hardness of the abrasive, the cost is relatively high and it is not suitable for industrial production. In the prior art, the cost can be reduced by combining diamond with auxiliary abrasives such as silicon carbide and white corundum, but there are still problems such as high abrasive wear and a narrow range of application, which need further improvement.

[0005] In view of the problems existing in the prior art, how to provide an abrasive with high hardness, low wear and low cost is a problem to be solved urgently in the present invention. Summary of the invention

[0006] The object of the present invention is to provide a high-strength abrasive based on diamond and a preparation method thereof, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides a high-strength abrasive based on diamond, characterized in that the abrasive comprises the following components in parts by weight: 40-70 parts of modified polyurethane, 10-20 parts of diamond, 10-25 parts of auxiliary abrasive, 5-10 parts of modified alumina, and 10-20 parts of mica powder;

[0008] The modified polyurethane is a polyurethane grafted with a pyridine bisphenol derivative.

[0009] As a further improvement, the modified polyurethane is prepared by reacting isophorone diisocyanate, trimethylolpropane, 4-hydroxyacetophenone and 4-trifluoromethylbenzaldehyde.

[0010] As a further improvement, the preparation method of the modified polyurethane comprises the following steps:

[0011] (1) under a nitrogen atmosphere, 4-hydroxyacetophenone, 4-trifluoromethylbenzaldehyde, ammonium acetate and an organic solvent are added to a flask, heated under reflux at 100-120° C., the reaction is completed, and post-processed to obtain a pyridine bisphenol derivative;

[0012] (2) dissolving the pyridine bisphenol derivative obtained in step (1) in an organic solvent, then adding cyclohexanone and trimethylolpropane thereto, and ultrasonically dispersing until completely dissolved;

[0013] (3) Under a nitrogen atmosphere, isophorone diisocyanate and an organic solvent are added to a flask, and the mixture is stirred at 30-50° C. to react. The mixed solution obtained in step (2) is then slowly added dropwise, and the mixture is heated to 70-90° C. and stirred to react. After the reaction is completed, post-treatment is performed to obtain a modified polyurethane.

[0014] As a further improvement, in step (1), the molar ratio of 4-hydroxyacetophenone to 4-trifluoromethylbenzaldehyde is 2-3:1.

[0015] As a further improvement, the modified alumina is prepared by reacting polyacrylic acid and alumina.

[0016] As a further improvement, the synthesis of the modified alumina comprises the following steps:

[0017] Dissolve polyacrylic acid in alkaline solution, then add the mixed solution and alumina into a flask, stir in a water bath at room temperature for 10-30 minutes, heat to 50-70°C, continue stirring for 30-40 minutes, slowly add sulfuric acid at this temperature to adjust the pH to 6-7, then cool to room temperature, and post-treat to obtain modified alumina.

[0018] As a further improvement, the auxiliary abrasive is at least one of green silicon carbide, black silicon carbide, white corundum, and boron carbide.

[0019] In order to have higher strength, the auxiliary abrasive is green silicon carbide.

[0020] As a further improvement, the weight ratio of the added amount of diamond to the auxiliary abrasive is 1:0.5-3.

[0021] As a further improvement, preferably, the weight ratio of the added amount of diamond to the auxiliary abrasive is 1:1-2.

[0022] The present invention provides a method for preparing a high-strength abrasive based on diamond, characterized in that it comprises the following steps:

[0023] Diamond, auxiliary abrasive, modified alumina and mica powder are mixed to obtain a mixed powder, which is dried at 90-110° C. to remove moisture, and then modified polyurethane is added and mixed at 170-190° C. for 1-3 hours. After mixing, the mixture is cooled to room temperature and sieved to obtain an abrasive.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The invention provides a high-strength abrasive based on diamond and a preparation method thereof, so that the prepared abrasive has a higher Shore hardness, indicating that the abrasive has high hardness and a wider range of applications, and has a high wear ratio, indicating that the wear amount is low, the wear resistance is good, and the service life of the abrasive is longer. DETAILED DESCRIPTION

[0026] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0027] In the following embodiments, except for modified polyurethane and modified alumina, the other compound monomers and related reagents used can be purchased from the market. Among them, diamond was purchased from Henan Hengwei Superhard Materials Co., Ltd., model W20, green silicon carbide was purchased from Zhengzhou Xinli Wear-Resistant Materials Co., Ltd., specification 240#, alumina was purchased from Zhengzhou Xinli Wear-Resistant Materials Co., Ltd., specification 6000#, and mica powder was purchased from Anhui Ge Rui New Materials Technology Co., Ltd., model GM-2.

[0028] The preparation method of modified polyurethane comprises the following steps:

[0029] (1) Under a nitrogen atmosphere, 5.4 g of 4-hydroxyacetophenone, 3.4 g of 4-trifluoromethylbenzaldehyde, 10.8 g of ammonium acetate and 20 mL of glacial acetic acid were added to a flask, and the mixture was heated under reflux at 120° C. for 2 h. After the reaction was completed, the mixture was cooled to room temperature, and the reaction solution was poured into 200 mL of water to precipitate a thick solid substance, which was filtered and vacuum dried to obtain a pyridine bisphenol derivative;

[0030] (2) dissolving 0.4 g of the pyridine bisphenol derivative obtained in step (1) in 5 mL of N,N-dimethylformamide and 15 mL of cyclohexanone, then adding 10 g of trimethylolpropane and dispersing by ultrasonication until it is completely dissolved;

[0031] (3) Under a nitrogen atmosphere, 52.2 g of isophorone diisocyanate, 50 mL of xylene, and 20 mL of butyl acetate were added to a flask, and the mixture was stirred and reacted at 40° C. for 20 min. The mixed solution obtained in step (2) was then slowly added dropwise, and the temperature was raised to 70° C. and the stirring reaction was continued for 2 h. After the reaction was completed, the solvent was removed by rotary evaporation to obtain a modified polyurethane.

[0032] The preparation method of polyurethane comprises the following steps:

[0033] Under a nitrogen atmosphere, 52.2 g of isophorone diisocyanate, 50 mL of xylene, and 20 mL of butyl acetate were added to a flask, and the mixture was stirred and reacted at 40 °C for 20 min. Subsequently, a mixed solution of 10 g of trimethylolpropane and 5 mL of N,N-dimethylformamide was slowly added dropwise, and the mixture was heated to 70 °C and stirred and reacted for 2 h. After the reaction was completed, the solvent was removed by rotary evaporation to obtain polyurethane.

[0034] The preparation method of modified alumina comprises the following steps:

[0035] Mix 20 g of polyacrylic acid with 50 mL of 3% sodium carbonate solution (sodium carbonate solution is a mixture of sodium carbonate and water), then add the mixture and 15 g of alumina into a flask, stir in a water bath at room temperature for 20 min, heat to 70°C and continue stirring for 40 min, slowly add sulfuric acid at this temperature to adjust the pH to 7, then cool to room temperature, filter, rinse with 50% dilute sulfuric acid and water in turn, and dry at 90°C to obtain modified alumina.

[0036] The preparation methods of Examples 1-3 and Comparative Examples 1-2 comprise the following steps:

[0037] Diamond, auxiliary abrasive, modified alumina and mica powder are mixed by weight to obtain a mixed powder, which is dried at 100°C to remove moisture, and then modified polyurethane is added and mixed at 170°C for 3 hours. After mixing, the mixture is cooled to room temperature and sieved with a sieve with a mesh size of 0.8 mm to obtain an abrasive.

[0038] The components and contents used in Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below:

[0039] Table 1

[0040] Experimental items (weight parts) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Modified polyurethane 45 58 70 / 58 Polyurethane / / / 58 / Diamond 10 14 17 14 14 Green Silicon Carbide 12 20 25 20 20 Modified Alumina 5 8 10 8 / Alumina / / / / 8 Mica powder 10 13 18 13 13

[0041] The hardness and wear ratio of a high-strength diamond-based abrasive prepared in Example 1-3 and Comparative Example 1-2 were tested as follows:

[0042] Hardness test: According to GB / T 2411-2008, using Shore A hardness tester;

[0043] Wear ratio: According to JB / T 3235-2013, 80# grit ceramic bonded silicon carbide parallel grinding wheel is selected, and the wear amount of the grinding wheel is M s (g) and the wear amount M of the specimen j The ratio of the ratio of (g) to the wear ratio of the sample is called the wear ratio E value, where E = M s (g) / M j (g).

[0044] The test results are shown in Table 2, as follows:

[0045] Table 2

[0046]

[0047]

[0048] It can be seen from Example 2 and Comparative Example 1 in Table 2 that, compared with the abrasive prepared using unmodified polyurethane, the abrasive prepared using modified polyurethane has higher Shore hardness and wear ratio, indicating that the modified polyurethane can improve the rigidity and stability between chain segments, so that the prepared abrasive has stronger hardness and better wear resistance.

[0049] It can be seen from Example 2 and Comparative Example 2 that compared with the abrasive prepared using unmodified alumina, the abrasive prepared using modified alumina has a higher Shore hardness and wear ratio, indicating that the modified alumina has a higher dispersibility, can improve the wear resistance of the abrasive, and can improve the hardness of the abrasive to a certain extent.

[0050] It can be seen from the test results of Examples 1-3 that the abrasive prepared by the preparation method provided by the present invention has a higher Shore hardness, indicating that the abrasive has a high hardness and a wider range of applications, and has a high wear ratio, indicating that the wear amount is low, the wear resistance is good, and the service life of the abrasive is longer.

[0051] The above implementation modes are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with this technology to understand the content of the present invention and implement it, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A high-strength abrasive based on diamond, characterized in that: The abrasive comprises the following components in parts by weight: 40-70 parts of modified polyurethane, 10-20 parts of diamond, 10-25 parts of auxiliary abrasive, 5-10 parts of modified aluminum oxide, and 10-20 parts of mica powder; The modified polyurethane is a polyurethane grafted with a pyridine bisphenol derivative.

2. A high-strength diamond-based abrasive according to claim 1, characterized in that: The modified polyurethane is prepared by reacting isophorone diisocyanate, trimethylolpropane, 4-hydroxyacetophenone and 4-trifluoromethylbenzaldehyde.

3. A high-strength diamond-based abrasive according to claim 1, characterized in that: The preparation method of the modified polyurethane comprises the following steps: (1) under a nitrogen atmosphere, 4-hydroxyacetophenone, 4-trifluoromethylbenzaldehyde, ammonium acetate and an organic solvent are added to a flask, heated under reflux at 100-120° C., the reaction is completed, and post-processed to obtain a pyridine bisphenol derivative; (2) dissolving the pyridine bisphenol derivative obtained in step (1) in an organic solvent, then adding trimethylolpropane thereto, and ultrasonically dispersing until it is completely dissolved; (3) Under a nitrogen atmosphere, isophorone diisocyanate and an organic solvent are added to a flask, and the mixture is stirred at 30-50° C. to react. The mixed solution obtained in step (2) is then slowly added dropwise, and the mixture is heated to 70-90° C. and stirred to react. After the reaction is completed, post-treatment is performed to obtain a modified polyurethane.

4. A high-strength diamond-based abrasive according to claim 3, characterized in that: In the step (1), the molar ratio of 4-hydroxyacetophenone to 4-trifluoromethylbenzaldehyde is 2-3:

1.

5. A high-strength diamond-based abrasive according to claim 1, characterized in that: The modified aluminum oxide is prepared by reacting polyacrylic acid and aluminum oxide.

6. A high-strength diamond-based abrasive according to claim 1, characterized in that: The synthesis of the modified alumina comprises the following steps: Dissolve polyacrylic acid in alkaline solution, then add the mixed solution and alumina into a flask, stir in a water bath at room temperature for 10-30 minutes, heat to 50-70°C, continue stirring for 30-40 minutes, slowly add sulfuric acid at this temperature to adjust the pH to 6-7, then cool to room temperature, and post-treat to obtain modified alumina.

7. A high-strength diamond-based abrasive according to claim 1, characterized in that: The auxiliary abrasive is at least one of green silicon carbide, black silicon carbide, white corundum and boron carbide.

8. A high-strength diamond-based abrasive according to claim 1, characterized in that: The weight ratio of the added amount of diamond to the auxiliary abrasive is 1:0.5-3.

9. A high-strength diamond-based abrasive according to claim 1, characterized in that: The weight ratio of the diamond to the auxiliary abrasive is 1:1-2.

10. A method for preparing a high-strength diamond-based abrasive according to any one of claims 1 to 9, characterized in that: The following steps are involved: Diamond, auxiliary abrasive, modified alumina and mica powder are mixed to obtain a mixed powder, which is dried at 90-110° C. to remove moisture, and then modified polyurethane is added and mixed at 170-190° C. for 1-3 hours. After mixing, the mixture is cooled to room temperature and sieved to obtain an abrasive.

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