Preparation method for agglomerated diamond, and use of agglomerated diamond

Abstract

A preparation method for an agglomerated diamond, and the use of the agglomerated diamond. The preparation method comprises the following steps: (1) mixing an epoxy resin with a modifier, a curing agent and a solvent until uniform, so as to prepare a modified epoxy resin binder, wherein the modifier is one or more of a thermoplastic resin and a rubber elastomer; (2) mixing a diamond micropowder, a temporary binder and the modified epoxy resin binder until uniform to prepare a mixed slurry, then subjecting the mixed slurry to spray granulation, and sieving same to obtain secondary particles with a particle size of less than or equal to 100 μm; and (3) further heating and curing the secondary particles, with the heating and curing temperature being 80-200ºC, so as to obtain agglomerated diamond particles. The method can prevent a reduction in the strength of the diamond caused by a high-temperature sintering process. Since a toughened epoxy resin is used as the binder, the agglomerated diamond prepared by means of the method is not easily broken, and thus a grinding or polishing solution material prepared from the agglomerated diamond has a high removal rate and is unlikely to scratch a surface of a workpiece.

Description

A preparation method of agglomerated diamond and its application Technical Field

[0001] The invention belongs to the technical field of diamond abrasive and grinding tool manufacturing, and particularly relates to a method for preparing agglomerated diamond by modifying and toughening epoxy resin and using the epoxy resin as a binder. Background Art

[0002] Diamond, with its high hardness, high thermal conductivity, and excellent chemical stability, is widely used in abrasives and grinding tools. Diamond abrasives can be used for grinding and polishing a wide range of materials, such as silicon carbide, sapphire, ceramics, stainless steel, and aluminum alloys. Bonded abrasives made with diamond, such as grinding wheels and pads, have important applications in semiconductor substrate thinning, optical glass polishing, and cemented carbide grinding.

[0003] Natural diamonds are expensive, and the diamonds currently used in abrasives and grinding tools are mainly artificial diamonds. Artificial diamonds can be divided into single-crystal diamonds and polycrystalline diamonds based on their structural type. Single-crystal diamonds have high hardness and a high material removal rate during the grinding process, but they also have problems such as high surface roughness and severe scratches on the workpiece. Polycrystalline diamonds, on the other hand, have structural defects and break into smaller particles during the grinding process. This feature can maintain continuous grinding force while preventing sharp edges from scratching the workpiece surface, achieving a processing effect with low surface roughness and few scratches. However, because polycrystalline diamonds are produced using directional blasting, the production cost is relatively high, which to some extent limits its scope of application.

[0004] Agglomerated diamond is a type of diamond particle formed by agglomerating diamond powder and a binder. Similar to polycrystalline diamond, agglomerated diamond exhibits excellent self-sharpening properties, ensuring material removal rates. Its spherical structure facilitates low surface roughness and prevents scratching. Furthermore, agglomerated diamond has lower production costs than polycrystalline diamond, thus offering a wider range of applications.

[0005] The strength of agglomerated diamond is crucial to its grinding performance. Currently, the existing technology uses traditional vitrified binders to produce agglomerated diamonds. This requires high-temperature sintering, which reduces the diamond's strength. Epoxy resins offer excellent mechanical properties, chemical stability, heat resistance, and corrosion resistance, but they are brittle in their cured state. Agglomerated diamonds produced with resin binders suffer from low strength, fragility, and low material removal rates.

[0006] Summary of the Invention

[0007] The purpose of the present invention is to address the deficiencies of the prior art and to propose a method for preparing agglomerated diamond by modifying epoxy resin to improve its toughness and using it as a binder.

[0008] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0009] The present invention modifies epoxy resin by introducing a thermoplastic resin or rubber elastomer into it to improve its toughness. An amine or anhydride curing agent is then added to the resin binder for subsequent curing. The modified epoxy resin is then mixed with diamond micropowder and a temporary adhesive, granulated, and sieved. The resulting granules are cured at a specified temperature to produce agglomerated diamond.

[0010] A method for preparing agglomerated diamonds comprises the following steps:

[0011] (1) uniformly mixing epoxy resin with a modifier, a curing agent, and a solvent to prepare a modified epoxy resin binder; the modifier is one or more of a thermoplastic resin and a rubber elastomer;

[0012] (2) mixing the diamond micropowder, the temporary binder and the modified epoxy resin binder to form a mixed slurry, and then spray-granulating the mixed slurry and sieving to obtain secondary particles with a particle size of ≤100 μm;

[0013] (3) The secondary particles are further heated and solidified at a temperature of 80-200° C. to obtain agglomerated diamond particles.

[0014] Preferably, the temporary binder in step (2) is one or more of dextrin, polyvinyl alcohol, polyethylene glycol and polyvinyl pyrrolidone.

[0015] Preferably, the epoxy resin in step (1) is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and polyphenol glycidyl ether epoxy resin; and the curing agent is one or more of amine curing agent and acid anhydride curing agent.

[0016] Preferably, the thermoplastic resin includes polysulfone, polyurethane, polysiloxane, polyethersulfone, polyamide and polyetheretherketone, and the rubber elastomer includes hydroxyl-terminated liquid nitrile rubber, carboxyl-terminated liquid nitrile rubber and amino-terminated liquid nitrile rubber.

[0017] Preferably, the curing agent includes one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, m-phenylenediamine, diethyltoluenediamine, isophoronediamine, maleic anhydride and phthalic anhydride.

[0018] Preferably, the solvent is one or more of acetone, butanone, toluene, xylene, ethyl acetate, butyl acetate, dichloromethane, methanol, ethanol, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

[0019] Preferably, the mass percentage of the solvent in the modified epoxy resin binder in step (1) is 50-99%, and the mass percentage of the solid component is 1-50%; wherein the mass ratio of each solid component is 30-80% epoxy resin, 5-50% modifier, and 5-30% curing agent, and the sum is 100%.

[0020] Preferably, the mass percentage of the solvent in the modified epoxy resin binder in step (1) is 70-95%, and the mass percentage of the solid component is 5-30%; wherein the mass ratio of each solid component is 40-75% epoxy resin, 10-40% modifier, and 10-20% curing agent, the sum of which is 100%.

[0021] Preferably, the mixed slurry in step (2) comprises, by mass percentage, 40-70% diamond powder, 5-55% modified epoxy resin binder, and 1-25% temporary adhesive.

[0022] Preferably, the mixed slurry in step (2) comprises, by mass percentage, 50-70% diamond powder, 15-40% modified epoxy resin binder, and 5-15% temporary adhesive.

[0023] Preferably, the diamond powder D50 in step (2) is 0.01-10 μm; the secondary particles D50 in step (2) is 0.1-50 μm; the heating and curing temperature in step (3) is 80-150° C., and the curing time is 4-24 h.

[0024] The agglomerated diamond prepared by the above method can be used as an abrasive to prepare a polishing liquid, or used to prepare a bonded abrasive tool.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The toughness of the modified epoxy resin binder of the present invention is improved, and the agglomerated diamond prepared by using the agglomerated diamond as a binder is not easy to break. The grinding or polishing liquid prepared by using the agglomerated diamond has a high material removal rate and is not easy to scratch the surface of the workpiece.

[0027] (2) The present invention uses modified epoxy resin to prepare agglomerated diamonds without the need for high-temperature sintering, thus avoiding the decrease in diamond strength caused by the high-temperature sintering process and saving energy consumption.

[0028] (3) The agglomerated diamond prepared by the present invention has excellent mechanical properties, chemical stability, heat resistance and corrosion resistance.

[0029] (4) The agglomerated diamond prepared by the present invention is used as an abrasive to prepare grinding and polishing liquids, and is used to prepare bonded abrasive tools such as grinding wheels and grinding pads, with a high material removal rate and is not prone to scratching the surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] FIG1 is a SEM image of the agglomerated diamond obtained in Example 1.

[0031] FIG2 is a particle size distribution diagram of the agglomerated diamond obtained in Example 1. DETAILED DESCRIPTION

[0032] The present invention will be described in further detail below with reference to specific examples, but the embodiments of the present invention are not limited thereto. For process parameters not particularly noted, conventional techniques may be used.

[0033] Example 1

[0034] (1) Weigh the required amount of epoxy resin E-51, then add the modifier carboxyl-terminated liquid nitrile rubber-40, the curing agent diethyltoluenediamine and the solvent acetone, and mix them evenly. The mass percentage of each solid component in the binder is 60% epoxy resin, 30% modifier, 10% curing agent, the mass percentage of the solid component in the binder is 10%, and the solvent is 90%;

[0035] (2) adding diamond powder with a D50 of 0.5 μm and polyethylene glycol 2000 as a temporary binder to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 60% diamond powder, 35% binder and 5% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 9 μm;

[0036] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 9 μm, and the secondary particles were heated and cured at 130° C. for 12 h to obtain agglomerated diamond particles. FIG1 is a SEM image of the agglomerated diamond obtained in this embodiment.

[0037] Example 2

[0038] (1) Weigh the required amount of epoxy resin E-44, then add the modifier hydroxyl-terminated liquid nitrile rubber-36, the curing agent ethylenediamine and the solvent butanone, and mix them evenly. The mass percentage of each solid component in the binder is 70% epoxy resin, 20% modifier, 10% curing agent, 20% solid component in the binder, and 80% solvent;

[0039] (2) adding diamond powder with a D50 of 0.02 μm and polyethylene glycol 4000 as a temporary binder to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 50% diamond powder, 40% binder and 10% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 5 μm;

[0040] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 5 μm, and the secondary particles were heated and cured at 110° C. for 24 h to obtain agglomerated diamond particles.

[0041] Example 3

[0042] (1) Weigh the required amount of epoxy resin F-170, then add the modifier TPU-1185A, the curing agent diethylenetriamine and the solvent dichloromethane. The mass percentage of each solid component in the binder is 70% epoxy resin, 15% modifier, 15% curing agent, 5% solid component mass percentage in the binder, and 95% solvent;

[0043] (2) adding diamond powder with a D50 of 0.05 μm and a temporary binder polyvinyl pyrrolidone K30 to the mixture and mixing them again to prepare a mixed slurry. The mass percentages of diamond powder, binder and temporary binder are 55% diamond powder, 40% binder and 5% temporary binder. The mixed slurry is then spray granulated to obtain particles with a D50 of 3 μm.

[0044] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of ∼3 μm, and the secondary particles were heated and cured at 120° C. for 14 h to obtain agglomerated diamond particles.

[0045] Example 4

[0046] (1) Weigh the required amount of epoxy resin E-44, then add the modifier TPU-1164D10, the curing agent hexamethylenediamine and the solvent acetone / N,N-dimethylformamide (v / v = 3 / 1). The mass percentage of each solid component in the binder is 75% epoxy resin, 10% modifier, 15% curing agent, 10% solid component in the binder, and 90% solvent.

[0047] (2) adding diamond powder with a D50 of 0.03 μm and a temporary binder polyvinyl pyrrolidone K60 to the mixture and mixing them again to form a mixed slurry. The mass percentages of diamond powder, binder and temporary binder are 65% diamond powder, 20% binder and 15% temporary binder. The mixed slurry is then spray granulated to obtain particles with a D50 of 5 μm.

[0048] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 5 μm, and the secondary particles were heated and cured at 140° C. for 6 h to obtain agglomerated diamond particles.

[0049] Example 5

[0050] (1) Weigh the required amount of epoxy resin F-170, then add the modifier carboxyl-terminated liquid nitrile rubber-40, the curing agent maleic anhydride and the solvent acetone / dichloromethane (v / v = 2 / 1). The mass percentage of each solid component in the binder is 40% epoxy resin, 40% modifier, 20% curing agent, 15% solid component mass percentage of the binder, and 85% solvent;

[0051] (2) adding diamond powder with a D50 of 0.2 μm and polyethylene glycol 600 as a temporary binder to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 70% diamond powder, 15% binder and 15% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 2 μm;

[0052] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of ∼2 μm, and the secondary particles were heated and cured at 150° C. for 4 h to obtain agglomerated diamond particles.

[0053] Example 6

[0054] (1) Weigh the required amount of epoxy resin E-51, then add the modifier TPU1195A, the curing agent diethyltoluenediamine and the solvent acetone, and mix them evenly. The mass percentage of each solid component in the binder is 60% epoxy resin, 30% modifier, 10% curing agent, 10% solid component mass percentage of the binder, and 90% solvent;

[0055] (2) adding diamond powder with a D50 of 0.02 μm and polyethylene glycol 4000 as a temporary binder to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 50% diamond powder, 40% binder and 10% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 5 μm;

[0056] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 5 μm, and the secondary particles were heated and cured at 110° C. for 12 h to obtain agglomerated diamond particles.

[0057] Example 7

[0058] (1) Weigh the required amount of epoxy resin E-51, then add the modifier carboxyl-terminated liquid nitrile rubber-40, the curing agent diethyltoluenediamine and the solvent acetone, and mix them evenly. The mass percentage of each solid component in the binder is 60% epoxy resin, 30% modifier, 10% curing agent, the mass percentage of the solid component in the binder is 10%, and the solvent is 90%;

[0059] (2) adding diamond powder with a D50 of 0.5 μm and a temporary binder polyethylene glycol 2000 to the mixture and mixing them again to prepare a mixed slurry. The mass percentages of diamond powder, binder and temporary binder are 40% diamond powder, 55% binder and 5% temporary binder. The mixed slurry is then spray granulated to obtain particles with a D50 of 15 μm.

[0060] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 15 μm, and the secondary particles were heated and cured at 130° C. for 12 h to obtain agglomerated diamond particles.

[0061] Example 8

[0062] (1) Weigh the required amount of epoxy resin E-51, then add the modifier carboxyl-terminated liquid nitrile rubber-40, the curing agent diethyltoluenediamine and the solvent acetone, and mix them evenly. The mass percentage of each solid component in the binder is 60% epoxy resin, 30% modifier, 10% curing agent, the mass percentage of the solid component in the binder is 10%, and the solvent is 90%;

[0063] (2) adding diamond powder with a D50 of 0.5 μm and a temporary binder polyethylene glycol 2000 to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 60% diamond powder, 35% binder and 5% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 10 μm;

[0064] (3) The above particles were sieved to obtain secondary particles with a particle size of less than 100 μm and a D50 of 10 μm, and the secondary particles were heated and cured at 80° C. for 12 h to obtain agglomerated diamond particles.

[0065] Comparative Example 1

[0066] (1) Weigh the required amount of epoxy resin E-51, then add the curing agent diethyltoluenediamine and the solvent acetone, and mix them evenly. The mass percentage of each solid component in the binder is 90% epoxy resin, 10% curing agent, 10% solid component in the binder, and 90% solvent;

[0067] (2) adding diamond powder with a D50 of 0.5 μm and a temporary binder polyethylene glycol 2000 to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 60% diamond powder, 35% binder and 5% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 10 μm;

[0068] (3) The above particles were sieved to obtain secondary particles with a D50 of 10 μm, and the secondary particles were heated and cured at 130° C. for 12 h to obtain agglomerated diamond particles.

[0069] Comparative Example 2

[0070] (1) Weigh the required amount of epoxy resin E-44, then add the curing agent ethylenediamine and the solvent butanone, and mix them evenly. The mass percentage of each solid component in the binder is 90% epoxy resin, 10% curing agent, 20% solid component in the binder, and 80% solvent;

[0071] (2) adding diamond powder with a D50 of 0.02 μm and polyethylene glycol 4000 as a temporary binder to the mixture and mixing them again to prepare a mixed slurry, wherein the mass percentages of diamond powder, binder and temporary binder are 50% diamond powder, 40% binder and 10% temporary binder, and then spray granulating the mixed slurry to obtain particles with a D50 of 5 μm;

[0072] (3) The above particles were sieved to obtain secondary particles with a D50 of 5 μm, and the secondary particles were heated and cured at 110° C. for 24 h to obtain agglomerated diamond particles.

[0073] The agglomerated diamonds in the above embodiments and comparative examples were formulated into a grinding liquid (except for the type of agglomerated diamonds, other parameters remained the same) to grind the silicon carbide substrate. The grinding liquid composition is as follows: 5 parts of agglomerated diamonds, 0.5 parts of sodium carboxymethyl cellulose, 0.5 parts of N-methyl pyrrolidone, 0.1 parts of lauryl alcohol, 5 parts of ethylene glycol and 88.9 parts of deionized water, totaling 100 parts. The grinding test conditions are as follows: the grinding equipment is a Jinyanxing YM-610 polishing machine, the turntable speed is 35rpm, the grinding liquid flow rate is 20ml / min, and the grinding time is 1h. The grinding data are shown in Table 1.

[0074] Table 1 Comparison of processing effects of different agglomerated diamonds

[0075] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for preparing agglomerated diamond, characterized in that: The steps include: (1) uniformly mixing epoxy resin with a modifier, a curing agent, and a solvent to prepare a modified epoxy resin binder; the modifier is one or more of a thermoplastic resin and a rubber elastomer; (2) mixing the diamond powder, temporary binder and modified epoxy resin binder uniformly to prepare a mixed slurry, and then spray granulating the mixed slurry and sieving to obtain secondary particles with a particle size of ≤100 μm; (3) The secondary particles are further heated and solidified at a temperature of 80-200° C. to obtain agglomerated diamond particles.

2. The preparation method according to claim 1, characterized in that The temporary binder in step (2) is one or more of dextrin, polyvinyl alcohol, polyethylene glycol and polyvinyl pyrrolidone.

3. The preparation method according to claim 2, characterized in that The epoxy resin in step (1) is one or more of bisphenol A epoxy resin, bisphenol F epoxy resin and polyphenol glycidyl ether epoxy resin; the curing agent is one or more of amine curing agent and acid anhydride curing agent; The modifier comprises one or more of polysulfone, polyurethane, polysiloxane, polyethersulfone, polyamide, polyetheretherketone, hydroxyl-terminated liquid nitrile rubber, carboxyl-terminated liquid nitrile rubber and amino-terminated liquid nitrile rubber; The curing agent includes one or more of ethylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, diethylaminopropylamine, m-phenylenediamine, diethyltoluenediamine, isophoronediamine, maleic anhydride and phthalic anhydride; The solvent is one or more of acetone, butanone, toluene, xylene, ethyl acetate, butyl acetate, dichloromethane, methanol, ethanol, tetrahydrofuran, N,N-dimethylformamide, and N,N-dimethylacetamide.

4. The preparation method according to claim 1, 2 or 3, characterized in that: In the step (1), the mass percentage of the solvent in the modified epoxy resin binder is 50-99%, and the mass percentage of the solid component is 1-50%; wherein the mass ratio of each solid component is 30-80% of epoxy resin, 5-50% of modifier, and 5-30% of curing agent.

5. The preparation method according to claim 4, characterized in that In step (1), the mass percentage of the solvent in the modified epoxy resin binder is 70-95%, and the mass percentage of the solid component is 5-30%; wherein the mass ratio of each solid component is 40-75% of epoxy resin, 10-40% of modifier, and 10-20% of curing agent.

6. The preparation method according to claim 4, characterized in that The mixed slurry in step (2) comprises, by mass percentage, 40-70% of diamond powder, 5-55% of modified epoxy resin binder, and 1-25% of temporary adhesive.

7. The preparation method according to claim 6, characterized in that The mixed slurry in step (2) comprises, by mass percentage, 50-70% of diamond powder, 15-40% of modified epoxy resin binder, and 5-15% of temporary adhesive.

8. The preparation method according to claim 1, characterized in that The diamond powder D50 in step (2) is 0.01-10 μm; the secondary particles D50 in step (2) is 0.1-50 μm; the heating and curing temperature in step (3) is 80-150° C., and the curing time is 4-24 hours.

9. Agglomerated diamond prepared by the method according to any one of claims 1 to 8.

10. The use of the agglomerated diamond according to claim 9, characterized in that: The agglomerated diamond is used as an abrasive to prepare a polishing liquid, or is used to prepare a bonded abrasive tool.

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