Novel elastic grinding block as well as preparation method and application thereof

Abstract

The invention provides a novel elastic grinding block and a preparation method and application thereof. The novel elastic grinding block comprises the following components in parts by weight: 15-40 parts of a diamond composite grinding material, 40-70 parts of modified polyisobutene, 0-5 parts of simethicone, 1-10 parts of rare earth oxide and 5-20 parts of a curing agent. The prepared elastic grinding block has the high material removal rate, is good in grinding performance and high in efficiency when applied to workpiece machining, can well grind and polish inner holes, blind holes, corners and the like, has the low surface roughness and the high glossiness, cannot generate defects such as shadows and grinding cracks on the surfaces of workpieces, and is suitable for large-scale production. The surface smoothness is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polishing, and in particular relates to a novel elastic grinding block and a preparation method and application thereof. Background Art

[0002] The main function of the grinding block is to perform fine processing on the workpiece surface through the cutting action of the abrasive to achieve the required size, shape and surface roughness. It is widely used in the processing of metal and non-metal materials.

[0003] Most grinding blocks are artificial grinding blocks made of abrasives and binders. Therefore, the life and technical indicators of the grinding blocks are determined by many factors, such as the properties of the abrasives and binders themselves, the ability of the binders to hold the abrasives, and the physical and chemical reactions that occur during the grinding process.

[0004] Diamond is widely used as an abrasive in the processing of hard materials due to its extremely high hardness, excellent wear resistance, high strength and other characteristics. Diamond abrasive block binders are divided into the following three types: metal type, ceramic type, and resin type binders. Among them, metal type binders have strong bonding strength and good toughness with diamond abrasive grains, and can withstand large loads. They have been used in the field of precision and ultra-precision grinding of brittle and hard materials, but they are prone to burns on workpieces, dark shadows, and wear marks during use. Ceramic binders have high elastic modulus and low fracture toughness, and are widely used in the processing of cemented carbide, glass, ceramics and other materials. However, ceramic binders have not yet achieved ideal results in terms of flexural strength, thermal conductivity, and interface bonding performance with diamond, which restricts their application in the field of high-precision grinding. Resin-type binder is one of the important abrasive block binders in industrial production, especially in the field of precision machining, with excellent processing characteristics. The bonding strength between the resin and the abrasive is high and the elasticity after molding is good. However, since the resin and the abrasive are the interface bonding between organic polymer materials and inorganic materials, the wettability of the resin to the abrasive is poor, which makes the abrasive block have the disadvantages of poor grindability and low hardness.

[0005] In view of the problems existing in the prior art, how to provide an elastic grinding block with good grinding performance, smooth surface of the workpiece after processing, and no defects such as dark shadows and wear marks is a problem to be solved urgently by the present invention. Summary of the invention

[0006] The purpose of the present invention is to provide a new elastic grinding block to solve the problems raised in the above background technology.

[0007] A further object of the present invention is to provide application of the novel elastic grinding block in the field of workpiece polishing.

[0008] To achieve the above object, the present invention provides a novel elastic grinding block, characterized in that it comprises the following components in parts by weight: 15-40 parts of diamond composite abrasive, 40-70 parts of modified polyisobutylene, 0-5 parts of dimethyl silicone oil, 1-10 parts of rare earth oxide, and 5-20 parts of curing agent;

[0009] The modified polyisobutylene is epoxidized polyisobutylene.

[0010] As a further improvement, the epoxidized polyisobutylene is prepared by reacting polyisobutylene and hydrogen peroxide.

[0011] As a further improvement, the synthesis of the epoxidized polyisobutylene comprises the following steps:

[0012] (1) polyisobutylene is stirred and dissolved in an organic solvent, and then formic acid is added, and condensed and stirred at low temperature for 30-60 minutes;

[0013] (2) Prepare a 30% hydrogen peroxide solution, then add phosphoric acid, stir and mix evenly, then slowly add it dropwise to step (1), and heat to 60-90° C., continue stirring and reacting for 4-6 hours. After the reaction is completed, post-process and obtain epoxidized polyisobutylene.

[0014] As a further improvement, the weight ratio of the added amount of polyisobutylene and hydrogen peroxide is 1:0.2-0.6.

[0015] As a further improvement, the rare earth oxide is at least one of cerium oxide, lanthanum oxide, praseodymium oxide and neodymium oxide.

[0016] As a further improvement, the rare earth oxide is at least one of cerium oxide and lanthanum oxide.

[0017] In order to have better polishing performance, preferably, the rare earth oxide is cerium oxide.

[0018] As a further improvement, the curing agent is at least one of methylhexahydrophthalic anhydride, phthalic anhydride, 4,4-diaminodiphenyl sulfone, and 2-methylimidazole.

[0019] In order to have a better curing effect, preferably, the curing agent is 2-methylimidazole.

[0020] As a further improvement, the method for preparing the diamond composite abrasive comprises the following steps:

[0021] 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 a diamond composite abrasive.

[0022] The present invention provides a novel elastic grinding block, which is characterized by comprising the following steps:

[0023] (1) Mixing diamond composite abrasive, dimethyl silicone oil, and rare earth oxide uniformly according to weight, and then adding modified polyisobutylene and curing agent and continuing to stir and mix;

[0024] (2) The mixed material obtained in step (1) is put into a reaction kettle for heating, then filled into a mold, and allowed to stand at room temperature for 5-10 hours for curing to obtain an elastic grinding block.

[0025] The invention provides an application of a novel elastic grinding block in the field of workpiece polishing.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The elastic grinding block prepared by the present invention has a high material removal rate, indicating that it has good grinding performance and high efficiency when used for workpiece processing. It can also perform good grinding and polishing on inner holes, blind holes, corners, etc. It has low surface roughness and high glossiness, indicating that no defects such as dark shadows and wear marks will be generated on the workpiece surface, thereby improving the surface finish. DETAILED DESCRIPTION

[0028] 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.

[0029] In the following embodiments, except for epoxidized polyisobutylene, modified alumina, modified polyurethane, and diamond composite abrasive, the remaining compound monomers and related reagents used can be purchased from the market, among which polyisobutylene was purchased from Jiangsu Rayne Environmental Protection Technology Co., Ltd., 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.

[0030] The synthesis of epoxidized polyisobutylene comprises the following steps:

[0031] (1) Dissolve 50 g of polyisobutylene in 40 mL of petroleum ether, then add 12 mL of formic acid and stir at 25 °C for 30 min;

[0032] (2) Prepare 65 g of a 30% hydrogen peroxide solution, then add 0.2 g of phosphoric acid, stir and mix evenly, then slowly add it dropwise to step (1), and slowly raise the temperature to 70° C. At this temperature, continue stirring and reacting for 5 h. After the reaction is completed, extract with distilled water, collect the organic phase, and remove the solvent by reduced pressure distillation to obtain epoxidized polyisobutylene.

[0033] The preparation method of modified alumina comprises the following steps:

[0034] 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.

[0035] The preparation method of modified polyurethane comprises the following steps:

[0036] (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;

[0037] (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;

[0038] (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.

[0039] The method for preparing a diamond composite abrasive comprises the following steps:

[0040] 14g of diamond, 20g of green silicon carbide, 8g of modified alumina and 13g of mica powder were mixed to obtain a mixed powder, which was dried at 100°C to remove moisture. Subsequently, 58g of modified polyurethane was added and mixed at 170°C for 3h. After the mixing was completed, the mixture was cooled to room temperature and sieved with a sieve with a mesh size of 0.8mm to obtain a diamond composite abrasive.

[0041] The preparation methods of Examples 1-4 and Comparative Examples 1-3 comprise the following steps:

[0042] (1) Mixing diamond composite abrasive, dimethyl silicone oil, and rare earth oxide uniformly according to weight, and then adding modified polyisobutylene and curing agent and continuing to stir and mix;

[0043] (2) The mixed material obtained in step (1) is placed in a reactor and heated at a temperature of 150° C., then filled into a mold and allowed to stand at room temperature for 8 hours for curing to obtain an elastic grinding block.

[0044] The components and contents used in Examples 1-4 and Comparative Examples 1-3 are shown in Table 1 below:

[0045] Table 1

[0046]

[0047]

[0048] The material removal rate, surface roughness and glossiness of a new type of elastic grinding block prepared in Examples 1-4 and Comparative Examples 1-3 were tested in the following manner:

[0049] Material removal rate: grinding blocks and ceramics were used to grind on an abrasive cloth and sandpaper grinding test machine to calculate the material removal rate. Each test was repeated three times and the average value was taken. The abrasive cloth and sandpaper grinding test machine was a ZRX-18099 abrasive cloth and sandpaper grinding test machine.

[0050] Surface roughness: Use a surface roughness measuring instrument to measure the surface roughness of the polished ceramics;

[0051] Glossiness: Let the polished workpiece dry, then wipe the tile surface clean with alcohol and a towel. Use a gloss meter to test 5×5=25 points on the clean ceramic surface, record and take the average value.

[0052] The measured results are shown in Table 2:

[0053] Table 2

[0054] <![CDATA[Material removal rate / (mm 3 / s)]]> Surface roughness / (μm) Glossiness / ° Example 1 0.88 0.36 71.6 Example 2 0.91 0.35 74.4 Example 3 0.96 0.28 78.5 Example 4 0.93 0.32 76.2 Comparative Example 1 0.85 0.71 53.9 Comparative Example 2 0.64 0.67 58.5 Comparative Example 3 0.79 0.76 50.6

[0055] It can be seen from Example 3 and Comparative Example 1 in Table 2 that, compared with the elastic abrasive block prepared by using only diamond as an abrasive, when the elastic abrasive block prepared by using diamond composite abrasive is applied to the polishing of the workpiece, the surface roughness of the workpiece is lower and the glossiness is higher, indicating that the surface of the workpiece will not produce defects such as shadows and wear marks, and to a certain extent, the material removal rate can also be improved, and the grinding performance and efficiency of the abrasive block can be improved.

[0056] It can be seen from Example 3 and Comparative Example 2 that compared with the elastic abrasive block prepared using unmodified polyisobutylene, the elastic abrasive block prepared using modified polyisobutylene has a higher material removal rate when applied to the polishing of the workpiece, indicating that modified polyisobutylene as a resin can make the material bond more dense, improve the grinding performance and efficiency of the material, and can also better polish the inner holes, blind holes, corners, etc., and can reduce the surface roughness of the workpiece and improve the glossiness to a certain extent.

[0057] It can be seen from Example 3 and Comparative Example 3 that, compared with the elastic abrasive block prepared without using rare earth oxide, the elastic abrasive block prepared with the participation of rare earth oxide has a higher material removal rate and glossiness and has a lower surface roughness when applied to the polishing of the workpiece, indicating that the elastic abrasive block prepared by the preparation method provided by the present invention has a high efficiency when applied to workpiece processing and will not produce defects such as dark shadows and wear marks on the workpiece surface.

[0058] It can be seen from the test results of Examples 1-4 that the elastic abrasive block prepared by the preparation method provided by the present invention has a higher material removal rate, indicating that the elastic abrasive block has good grinding performance and high efficiency when used for workpiece processing. Through experiments, it is found that even for easily overlooked places such as inner holes, blind holes, and corners, it can have good grinding and polishing, with lower surface roughness and higher glossiness, indicating that no defects such as dark shadows and wear marks will be generated on the workpiece surface, thereby improving the surface finish.

[0059] 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 new elastic grinding block, characterized in that: The invention comprises the following components in parts by weight: 15-40 parts of diamond composite abrasive, 40-70 parts of modified polyisobutylene, 0-5 parts of dimethyl silicone oil, 1-10 parts of rare earth oxide, and 5-20 parts of curing agent; The modified polyisobutylene is epoxidized polyisobutylene.

2. A new elastic grinding block according to claim 1, characterized in that: The epoxidized polyisobutylene is prepared by reacting polyisobutylene and hydrogen peroxide.

3. A new elastic grinding block according to claim 1, characterized in that: The synthesis of the epoxidized polyisobutylene comprises the following steps: (1) polyisobutylene is stirred and dissolved in an organic solvent, and then formic acid is added, and condensed and stirred at low temperature for 30-60 minutes; (2) Prepare a 30% hydrogen peroxide solution, then add phosphoric acid, stir and mix evenly, then slowly add it dropwise to step (1), and heat to 60-90° C., continue stirring and reacting for 4-6 hours. After the reaction is completed, post-process and obtain epoxidized polyisobutylene.

4. A new elastic grinding block according to claim 3, characterized in that: The weight ratio of the added amount of polyisobutylene and hydrogen peroxide is 1:0.2-0.

6.

5. A new elastic grinding block according to claim 1, characterized in that: The rare earth oxide is at least one of cerium oxide, lanthanum oxide, praseodymium oxide and neodymium oxide.

6. A novel elastic grinding block according to claim 1, characterized in that: The rare earth oxide is at least one of cerium oxide and lanthanum oxide.

7. A novel elastic grinding block according to claim 1, characterized in that: The curing agent is at least one of methyl hexahydrophthalic anhydride, phthalic anhydride, 4,4-diaminodiphenyl sulfone and 2-methylimidazole.

8. The novel elastic grinding block according to claim 1 is characterized in that: The method for preparing the diamond composite abrasive comprises the following steps: 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 a diamond composite abrasive.

9. A novel elastic grinding block according to any one of claims 1 to 8, characterized in that: The preparation of the novel elastic grinding block comprises the following steps: (1) Mixing diamond composite abrasive, dimethyl silicone oil, and rare earth oxide uniformly according to weight, and then adding modified polyisobutylene and curing agent and continuing to stir and mix; (2) The mixed material obtained in step (1) is put into a reaction kettle for heating, then filled into a mold, and allowed to stand at room temperature for 5-10 hours for curing to obtain an elastic grinding block.

10. Application of the novel elastic grinding block according to claim 9 in the field of workpiece polishing.

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