JP2008115303A - Resin material for polishing tool and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polishing material which has fine diamond particles of a submicrometer class size dispersed and held in a resinous bond material or matrix material in the state of the primary particles without causing cohesion. <P>SOLUTION: The fine diamond-dispersed resin material, in which particle size-regulated diamond particles are singly coated in the non-cohesion state with a resin layer, is obtained by the manufacturing method comprising the following steps: (1) hydrophilizing fine diamond powders having a D<SB>50</SB>average particle size of ≤1,000 nm by bonding a hydrophilic functional group to them or making it adsorbed on them; (2) heating the hydrophilized diamond particles at the hydrogen termination temperature in a hydrogen atmosphere to make the surfaces of the diamond particles hydrogen-terminated; (3) combining the hydrogen-terminated diamond particles, a resin and an organic medium to prepare slurry having the diamond particles dispersed therein; and (4) separating/removing the organic medium to recover the diamond-containing resin in the form of powders or flakes. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a polishing tool resin material and a method for producing the same, and in particular, finely divided diamond fine particles having a submicron grade particle size, which are individually coated with a resin layer in a primary particle state (non-aggregated state). The present invention relates to a resin material in which diamond particles are effectively dispersed, and a method for manufacturing an abrasive tool using the resin material.

  Along with the rapid advancement of precision processing, in the field of polishing using diamond abrasive grains, the tendency to use finer abrasive grains has become prominent with the aim of achieving a finishing surface accuracy of angstrom level. Diamond particles of 500 nm or less have been widely used.

  Even diamond, which is generally considered as a chemically stable substance, shows strong surface properties as the particle size decreases. It is recognized that Therefore, if it is used as it is with being fixed to the polishing tool, it apparently behaves as coarse particles, which may cause scratches on the processed surface.

  Therefore, in this polishing process using diamond in the submicron region, it is put to practical use as a slurry of free abrasive grains in which abrasive grains are dispersed in an oily or aqueous medium (liquid) in the form of isolated particles. The diamond abrasive grains in the slurry are held on a polishing disk or polishing cloth and contribute to processing, but the retention rate is generally low, and the proportion of abrasive grains that flow out without contributing to processing is at a level that can not be ignored. is there.

Submicron-grade diamond powder is often used as a water-based slurry, and it is well known that for this purpose, the surface of diamond particles is actively made hydrophilic by oxidation treatment.
Japanese Patent No.2691884

As a measure for preventing aggregation in a dry powder for a slurry using an oily medium, one of the present inventors previously bonded a hydrogen atom to a dangling bond (unbonded bond) existing on the diamond particle surface. It was found that it is effective to stabilize. Based on this finding, submicron diamond powder which hardly aggregates is obtained by hydrogen-termination of active sites on the surface of diamond particles.
JP 2001-329252 A

Furthermore, according to the knowledge of the present inventors, the effect of hydrogen termination treatment on the diamond is recognized from around 500 ° C. when heated in a hydrogen atmosphere. That is, the absorption peak height attributed to OH stretching, which was observed in the vicinity of 3000 to 3600 cm ⁻¹ in the infrared absorption analysis, was reduced, and instead was not recognized in the surface hydrophilic diamond, but near 2800 to 3000 cm ^−1. An absorption peak attributed to the CH stretching observed in FIG. This absorption peak becomes prominent when heated at 600 ° C., and an absorption peak attributed to OH stretching is generally not observed in the heat treatment at 800 ° C., so it is considered that the hydrogen termination treatment is almost completed. During this time, it is recognized that a reaction in which hydrogen is bonded to and stabilized by dangling bonds generated by desorption of oxygen from the C—O bond site is also advanced.

  Even if the heating is continued at a temperature exceeding 800 ° C., desorption of CO gas from the diamond surface is observed, so that it is presumed that there is oxygen firmly bonded to the diamond surface. Therefore, heat treatment at a temperature of 800 ° C. or higher in hydrogen is effective for removing bound oxygen from the diamond surface. However, when the heat treatment exceeds 1000 ° C., the structure of the diamond powder particle surface collapses and becomes a structure covered with non-diamond carbon, and the hydrogen termination effect tends to be unclear.

  Since hydrogen-terminated diamond is easy to disperse in an oil-based dispersion medium (organic medium) made of an organic compound, fine diamond particles are transformed into a resin material that has solubility in an organic medium by applying hydrogen termination treatment. Can be uniformly dispersed. In an experiment by the present inventors, submicron diamond having an average particle diameter of 50 nm is suspended in a solvent for 6 hours after dispersion up to 0.03% in methanol, 0.34% in propanol, and 0.41% in acetone. The result of keeping was obtained. That is, it is understood that the diamond surface is wet with these solvents. Further, immediately after ultrasonic dispersion, the above diamond can be present in a pseudo-suspended state.

  Accordingly, one of the main objects of the present invention is polishing in which fine diamond particles of submicron grade are not aggregated, that is, are dispersed and held in a resinous bond material or matrix material in the form of primary particles. To provide materials. Another object is to provide a method capable of efficiently producing such an abrasive. Yet another object is to provide a method of manufacturing an abrasive tool using such materials.

The present invention, in one aspect, is characterized in that diamond particles constituting diamond powder having a D ₅₀ value average particle diameter of 1000 nm or less, particularly 500 nm or less, are individually coated with a resin layer in a non-aggregated state. The present invention relates to a powder or flaky resin-coated fine diamond powder. Here, the term “coating” includes a state in which individual diamond particles are separated from other adjacent particles by the resin regardless of the relative volume of the diamond particles to be coated and the resin as the coating material. Shall be.

The fine diamond-dispersed resin material is produced effectively by a method comprising the following steps and constituting another aspect of the present invention.
(1) a step of making hydrophilic by bonding or adsorbing hydrophilic functional groups to fine diamond powder having a D ₅₀ value average particle diameter of 1000 nm or less, particularly 500 nm or less,
(2) heating the hydrophilized diamond particles in a hydrogen atmosphere at a hydrogen termination temperature to hydrogenate the diamond particle surface;
(3) combining the hydrogen-terminated diamond particles, a resin, and an organic medium to produce a suspension in which diamond particles are dispersed;
(4) A step of separating and removing the organic medium and recovering the diamond-containing resin in the form of powder or flakes.

  As described above, according to the present invention, it is possible to use fine diamond particles, which can be used only as a slurry in the past, for precision polishing in a configuration in which the fine particles are held as primary particles in a resin.

  In the present invention, the abrasive grains are used not as a slurry of loose abrasive grains, but as fixed abrasive grains held in a tool, thereby improving productivity by effectively using abrasive grains and reducing processing costs. In addition, it is possible to reduce the burden on environmental conservation by reducing the amount of waste.

The method of the present invention can be applied to fine diamond particles, and can be applied to finely sized diamond powder (particle aggregate) whose D ₅₀ average value is 1000 nm (1 μm) or less to effectively disperse primary particles. It is possible to make a body.

In the present invention, the fine diamond powder dispersed in the resin material has a D ₅₀ value average particle diameter of 1000 nm or less, particularly 500 nm or less, more preferably 200 nm or less. Powder refers to an aggregate of particles. The size (particle size) of each particle constituting the powder has a distribution range that varies depending on the classification accuracy on both sides of the average value expressed as the D ₅₀ value, which is typically a D ₁₀ value relative to the D ₅₀ value and Characterized by the ratio of D ₉₀ values. In the present invention, fine diamond powder finely sized by precision classification is used, and the ratio of these parameters D ₁₀ / D ₅₀ and D ₉₀ / D ₅₀ is particularly ½ for precision processing polishing. Those above and below 2 are preferred.

  In addition, individual particles having a particle size of 2000 nm (2 μm) or less can be used. Larger particles can be mixed with the matrix material by dry and wet mixing methods according to the prior art, and it is difficult to maintain a suspended state in an organic medium by ordinary methods. Excluded from the subject of the invention. On the other hand, the lower limit can be up to 3 nm, the smallest size available at present.

  In the present invention, fine diamond dispersed in a resin material is given lipophilicity or hydrophobicity by hydrogen termination treatment, and then combined with a dispersion medium or solvent made of a specific organic compound. “Combination” refers to an operation in which a plurality of different substances are present near or around each other, and particularly an operation in which solid particles or a second liquid having a different composition is added to the first liquid. For this operation, various methods described later can be used.

  Hydrogen termination treatment is an operation of adding hydrogen atoms to unbonded hands that have not been used for bonding with the adjacent carbon atoms among the bonds of carbon atoms on the diamond surface. This treatment makes the diamond particles lipophilic. (Hydrophobic) is imparted.

The above hydrogen termination treatment can improve the efficiency by previously hydrophilizing the diamond to be treated. In the present invention, hydrophilized diamond is used as the material to be treated. Although not essential, in particular, prior to hydrogen termination treatment, a hydrophilic functional group or atomic group is bonded to or adsorbed on the surface of diamond particles based on a known technique, so that C═O or C—OH bond is formed on the surface carbon atom. It is extremely effective to provide
Japanese Patent No.2691884

  The hydrogen termination treatment can be achieved by heating the diamond particles that have been previously hydrophilized as described above in a hydrogen atmosphere at a hydrogen termination temperature of 500 to 1000 ° C., particularly preferably at 600 to 800 ° C.

  Hydrogen-terminated diamond particles are homogenized in combination with a resin and an organic solvent to prepare a suspension in which diamond particles are dispersed. The following various methods can be used for this. For example, a medium for dispersing and suspending diamond particles (dispersion medium) and a medium (solvent) for dissolving a matrix constituent resin, i.e., a holding material component for dispersing and containing diamond particles in applications such as a polishing tool, respectively It is effective to use different types of organic compounds having different or mutually soluble (compatible) properties, and after mixing them into solutions or dispersions or suspensions, mixing the two solutions.

  Alternatively, after hydrogen-terminated diamond particles are dispersed and suspended in an organic medium, the matrix-constituting resin can be added and dissolved in a solid / powder or fluid state, and the whole can be mixed and homogenized.

  Alternatively, after the matrix-constituting resin is dissolved in an organic medium, mixed and homogenized, hydrogen-terminated diamond particles are added to the solution, or the solution is allowed to penetrate into the gaps between the hydrogen-terminated diamond particles. It is valid.

  The fine diamond powder combined with the matrix-constituting resin and dispersed and suspended in the medium is uniformly mixed, and then heated under normal pressure or reduced pressure to evaporate and remove the dispersion medium and solvent, for example, Resin holding fine diamond particles in a dispersed state can be recovered in the form of powder or flakes.

  In the case of a dispersion medium that contains diamond particles in a suspended state exceeding the suspension limit, the resin and diamond are intimately mixed by using the instantaneous drying method of the mixed product including spray drying as the drying method. Raw material powder is obtained.

  For use as a polishing tool, a thermoplastic resin can be used as the resin material that forms the matrix and fixes the diamond particles. However, from the standpoint of avoiding the trouble of softening due to polishing heat during use, it is thermosetting. A resin is more preferable. Examples of such resins include phenol resin, epoxy resin, melamine resin, urea resin, urethane resin, alkyd resin, unsaturated polyester, and the like.

  As an organic medium (that is, a dispersion medium or a solvent) used in the present invention, the above-mentioned resin raw materials and precursors are dissolved, the affinity for hydrogen-terminated diamond is high, and the properties of the resin material are not significantly changed. Substances which can be separated by distillation in the temperature range, in particular those having a boiling point of 120 ° C. or less are preferred. Such an organic medium can be selected from a wide range such as alcohols, ketones, chain hydrocarbons, cyclic hydrocarbons, and acetates. Further, thinners called lacquer thinner, urethane thinner, epoxy thinner, acrylic thinner, and melamine thinner can also be used.

  Since these organic media can be recovered by distillation and used repeatedly, media with low dispersibility (suspension limit) of diamond can also be used. In addition, since the dispersion medium and the solvent can be recovered in a temperature range that does not cause alteration of the resin material by using vacuum distillation means, in this sense, the condition of low boiling point is not an essential requirement for the organic medium.

  From the viewpoint of polishing performance, diamond particles as a starting material treated by the method of the present invention were synthesized under static ultrahigh pressure, that is, in the presence of a catalytic metal, under static ultrahigh pressure and high temperature conditions by pressing. Single crystalline diamond particles converted from non-diamond carbon, manufactured and subjected to crushing and classification processes are particularly preferred.

In the present invention, activated carbon atoms on the surface of diamond particles are terminated with hydrogen, and by this treatment, the absorption spectrum of the powder by a Fourier transform infrared spectrophotometer (FTIR) is observed in the vicinity of 2800 to 3000 cm ^−1. The height of the absorption peak attributed to CH stretching is equal to or higher than the height of the absorption peak attributed to OH stretching observed in the vicinity of 3000 to 3600 cm ⁻¹ .

  The starting diamond particles may also be polycrystalline agglomerates synthesized under dynamic ultra-high pressure by detonation of explosives and subjected to a crushing step, provided that they substantially exhibit a diamond structure. It can be used in the same manner because it can be agglomerated during synthesis and suspended in water in a state close to a single particle. In this case, a wet treatment at 200 ° C. or higher using an oxidizing agent or a dry treatment at 300 ° C. or higher using air or an oxidizing gas is effective as a treatment method.

  It has been confirmed by infrared absorption analysis that a hydrophilic oxygen-containing functional group such as carbonyl, carboxyl, or hydroxyl group exists in an adsorbed or bonded state on the diamond surface subjected to this treatment. It is understood that dangling bonds that are triggered by the elimination of these functional groups during heating are the starting points, and the bonds that occur between adjacent particles are the origin of aggregation.

The diamond particles used as a starting material in the production method of the present invention desirably have a SP ³ structure on the surface from the viewpoint of ensuring wettability to an organic medium and polishing performance.

In the method of the present invention, a resin material containing fine diamond with a high degree of dispersion in the matrix resin is effectively obtained, and this high dispersibility is exhibited even in a fine particle size region. This feature is obtained in the submicron region in which it is difficult to sufficiently mix the diamond abrasive grains and the resin of the matrix constituent material by the conventional method in the manufacturing process of the polishing tool, particularly for the powder having a D ₅₀ value average particle diameter of 200 nm or less. Especially noticeable.

  The diamond content in the matrix resin is preferably 50 (12.5 vol%) or less, more preferably 25 or less in terms of concentration, since the particle size of individual particles is small. On the other hand, when a polishing tool is manufactured, a resin lump containing diamond is formed into islands in the resin ground by mixing submicron diamond-dispersed resin and resin-only powder and filling and molding the mold. It is also possible to have a configuration dispersed in the above.

  In the present invention, it is important that individual particles whose surfaces are coated with a resin are present as primary particles (single particles). The resin-coated diamond can be prepared by immersing diamond wetted with an organic solvent in an organic solvent in which the resin is dissolved.

  On the other hand, with respect to the organic solvent, it is possible to increase the time during which the diamond particles are held in a suspended state by increasing the concentration of the resin material to increase the viscosity of the solvent. The organic medium to which the diamond particles and the resin material are added is subjected to various known methods such as stirring, ultrasonic irradiation, bead mill mixing, paint shaker, etc., as necessary, so as to ensure uniform mixing of the diamond and the resin. To.

  When the organic solvent is removed from the organic solvent in a state where the diamond and the resin are uniformly mixed and dried, a powder or flaky resin material in which submicron diamond fine particles are dispersed and fixed in a primary particle state is obtained. .

  The obtained resin material can be molded into a tool material using a normal resin molding technique. In particular, a pressure molding method using a heating means such as hot pressing or injection molding is preferable, and a fine diamond particle-dispersed tool or tool material substantially free of pores can be obtained. When the presence of pores does not become an obstacle, a casting method can be used, and a sheet can be formed by rolling or roll forming as necessary.

MD50 grade diamond powder D ₅₀ value average particle diameter 50nm as abrasive grains (Tomei Diamond Co. product), with phenol resin PR8000 (Sumitomo Bakelite Co. product) as a matrix constituent material. Since MD50 has hydrophilic functional groups bonded or adsorbed on its surface, it was kept at 700 ° C. in hydrogen as a preliminary operation, and the diamond particle surface was terminated with hydrogen. To 50 g of the treated diamond, 500 ml of methanol was added and dispersed with ultrasound to form a suspension.

  500 g of phenol resin PR8000 as a matrix constituent material was weighed and dissolved in 1000 ml of methanol to obtain a transparent brown liquid.

  Add the above-mentioned first methanol solution in which diamond is suspended to the second methanol solution in which the above phenol resin is dissolved, and then rapidly distill into the heating vessel while stirring to separate and remove the methanol. did.

  The obtained diamond-containing phenol resin was lightly crushed in a mortar to obtain brown pellets or powdery submicron diamond dispersion resin. Aggregates of diamond powder were not observed in this resin, and it was confirmed by SEM observation that the surface of each powder particle was covered with a phenol resin.

  Next, a lapping grindstone was manufactured using the above resin as a tool molding raw material powder. A polished carbon steel disk with a diameter of 150 mm is fitted in the mold frame and kept horizontal, filled with 80 g of raw material powder and leveled, and then 120 g of phenolic resin PR8000 powder is filled flat. did.

  A press plate is placed on top of this and a load of 30 tons is applied by a hydraulic press. The mold is heated to 200 ° C to simultaneously cure the molding raw material powder and the phenolic resin PR8000 powder. Got. This material was further cured in a dryer at 200 ° C. for 12 hours, and then fixed on a grinding wheel substrate made of Silmin using an adhesive (Bond E250: manufactured by Konishi Co., Ltd.), # 800 Surface grinding and truing of the grindstone surface were carried out using a GC grindstone.

  MD100 grade diamond (Tomei Diamond Co., Ltd. product) abrasive grains having an average particle diameter of 100 nm was mixed in an epoxy resin (Epiform F-246: Somaru Co., Ltd. product). Since the surface of MD100 is also hydrophilic, the diamond particle surface was terminated with hydrogen by heating at 700 ° C. in hydrogen in a preliminary operation as in Example 1. To 30 g of the treated diamond, 500 ml of acetone was added and dispersed with ultrasonic waves to obtain a suspension.

  100 g of the epoxy resin was weighed and dispersed in 1000 ml of methyl ethyl ketone to obtain a transparent solution. The above-mentioned diamond suspension acetone was added to methyl ethyl ketone in which the epoxy resin was dissolved, and the mixture was thoroughly mixed using a bead mill, and the dispersion medium and solvent were evaporated and separated using a distillation apparatus equipped with a stirrer.

  The obtained diamond-dispersed epoxy resin was ground in a mortar and then passed through an 80-mesh sieve to obtain a white powdery submicron diamond-dispersed resin. To this resin, 200 g of triazine resin BT2680 (Mitsubishi Gas Chemical Co., Ltd.) powder was added and thoroughly mixed by dry process to obtain a tool molding raw material powder.

  Next, a lapping grindstone was produced by the same method as in Example 1. The mold is 150 mm in diameter, the same as in Example 1. 160 g of raw material powder is leveled and filled, and the mold is heated to 230 ° C. while applying a load of 40 tons with a hydraulic press. Then, a lapping machine material having a thickness of about 6.5 mm was obtained.

  This material was further cured in a dryer for 12 hours at 230 ° C., and then fixed on a grinding wheel substrate made of Silmine using an adhesive (Bond E250: manufactured by Konishi Co., Ltd.), # 800 Surface grinding and truing of the grindstone surface were carried out using a GC grindstone.

A detonation diamond having a specific surface area of 300 m ² / g and having a primary particle diameter of 5 to 10 nm was used as the abrasive grains. The same phenol resin PR8000 (product of Sumitomo Bakelite Co., Ltd.) as in Example 1 was used as a resin material for holding diamond.

  Detonation diamond is first subjected to heat treatment in molten sodium hydroxide as a purification treatment, then subjected to surface oxidation treatment by boiling in a nitric acid-sulfuric acid mixed solution to form a hydrophilic functional group on the surface, and 700 ° C. in hydrogen. The surface of the diamond particle was terminated with hydrogen. To 5 g of the treated diamond, 200 ml of methyl ethyl ketone was added and dispersed with ultrasound to form a suspension.

  500 g of phenolic resin PR8000 as a matrix material was weighed and dissolved in 1000 ml of methyl ethyl ketone to obtain a transparent brown solution.

  The above-mentioned diamond-dispersed methyl ethyl ketone suspension was added to the methyl ethyl ketone solution in which the phenol resin was dissolved, and the mixture was thoroughly mixed by ultrasonic irradiation, and methyl ethyl ketone was evaporated and separated using a distillation apparatus equipped with a stirrer.

  The obtained diamond-dispersed resin was lightly crushed in a mortar to obtain a submicron diamond-dispersed resin in the form of a brown powder used as a tool molding raw material. The above steps are the same as those in the first embodiment.

  For the production of the lapping grindstone using this molding raw material powder, a carbon steel mold for a grindstone diameter of 100 mm was used. A molding raw material powder weight of 50 g was flattened, and 50 g of phenol resin PR8000 powder was filled flatly thereon. A pressing plate is placed on top of this, and the mold is heated to 200 ° C while applying a load of 10 tons with a hydraulic press. The molding raw material powder and phenol resin PR8000 powder are cured simultaneously, and a lapping machine with a thickness of about 10 mm. I got the material.

  This material was further cured in a dryer at 200 ° C. for 12 hours and then sufficiently cured, and then fixed on a steel grindstone substrate using an adhesive (bond E250) to obtain a lap grindstone for precision finishing. .

A suspension was prepared by dispersing 20 g of IRM 0-2 grade diamond fine powder (D ₅₀ = 950 nm) in 1000 ml of propanol, and a solution in which phenol resin PR8000 was dissolved in 200 ml of 55 g propanol was prepared. Both liquids were sufficiently mixed by ultrasonic irradiation, and the dispersion medium and solvent were separated and recovered by distillation at an oil roast of 110 ° C. to obtain a bulky phenol resin in which 12 vol% of submicron diamond particles were dispersed and held. This was pulverized and passed through an 80-mesh sieve to obtain a raw material powder for producing a grinding wheel.

D ₅₀ average particle size as the abrasive grains with a is Tomei Diamond Co., Ltd. MD20 grade diamond fines, by Sumitomo Bakelite phenolic resin as a matrix material PR8000 24nm. As a preliminary operation, MD20 was reoxidized by boiling in 9 parts sulfuric acid – 1 part nitric acid – 0.5 parts potassium nitrate (volume ratio), then kept at 700 ° C in hydrogen, and terminated with hydrogen on the diamond particle surface. Treated. To 4 g of the treated diamond, 1000 ml of acetone was added and dispersed with ultrasound to form a suspension.

200 g of phenol resin PR8000 (powder) was weighed as a matrix material and added to the above diamond suspension little by little to completely dissolve it. The resulting viscous brown diamond suspension was distilled to separate and collect acetone. On the other hand, the collected diamond mixed matrix was lightly crushed in a mortar to obtain a brown powdery submicron diamond dispersion resin. Agglomerates of diamond powder were not observed in this resin, and it was confirmed by SEM observation that the surface of each powder particle was covered with a phenol resin.

Claims (26)

  A powdery or flaky resin-coated fine diamond material, wherein diamond particles constituting the sized diamond powder are individually coated with a resin layer in a non-aggregated state. D ₅₀ value average particle size of the diamond powder is 1000nm or less, the resin-coated fine diamond material according to claim 1. The resin-coated fine diamond material according to claim 1, wherein the diamond powder has a D ₅₀ value average particle diameter of 500 nm or less. D ₅₀ value average particle size of the diamond powder is 200nm or less, the resin-coated fine diamond material according to any one of claims 1 to 3. The resin-coated fine diamond material according to any one of claims 1 to 4, wherein the ratio of the D ₁₀ value and the D ₉₀ value to the D ₅₀ value average particle diameter of the diamond powder is 1/2 or more and 2 or less, respectively.   The resin-coated fine diamond material according to claim 1, wherein the primary particle diameter of the diamond particles is 2 µm or less and 3 nm or more.   The resin-coated fine diamond material according to claim 1, wherein the diamond particles are single crystalline particles synthesized under a static ultrahigh pressure and subjected to a crushing and classification process.   The resin-coated fine diamond material according to claim 1, wherein the diamond particles are polycrystalline aggregated particles synthesized under dynamic ultrahigh pressure and subjected to a crushing step. The resin-coated fine diamond material according to claim 1, wherein carbon atoms on the surface of the diamond particles maintain an SP ³ structure.   The resin-coated fine diamond material according to claim 1, wherein the resin contains one kind selected from a phenol resin, a polyimide resin, a urethane resin, an acrylic resin, an epoxy resin, and a melamine resin.   A fine diamond particle-dispersed resin molding material containing the resin-coated fine diamond according to claim 1.   The fine diamond particle-dispersed resin molding material according to claim 11, which is a matrix material for producing a diamond polishing tool.   A diamond polishing tool comprising the resin-coated fine diamond according to claim 1. A method for producing a fine diamond-dispersed resin material containing the following steps:
(1) A step of making hydrophilic by bonding or adsorbing a hydrophilic functional group to a fine diamond powder having a D ₅₀ value average particle diameter of 1000 nm or less;
(2) heating the hydrophilized diamond particles in a hydrogen atmosphere at a hydrogen termination temperature to hydrogenate the diamond particle surface;
(3) A step of preparing a suspension in which diamond particles are dispersed by combining the hydrogen-terminated diamond particles, a resin, and an organic medium.
(4) A step of separating and removing the organic medium and recovering the diamond-containing resin in the form of powder or flakes.  In the above step (3), the hydrogen-terminated diamond particles and the matrix-constituting resin are dispersed and suspended or dissolved in the same or different compatible organic medium, respectively, to obtain a dispersion and suspension, and then the two solutions are mixed. The method of claim 14, wherein:   The method according to claim 14, wherein, in the step (3), after the hydrogen-terminated diamond particles are dispersed and suspended in an organic medium, the matrix-constituting resin is added and dissolved, and the whole is mixed.   15. The method according to claim 14, wherein in step (3), the hydrogen-terminated diamond particles are added after the matrix-constituting resin is dissolved and mixed in an organic medium.   The method according to claim 14, wherein, in the step (3), the matrix-constituting resin is dissolved and mixed in an organic medium and then permeated into the gaps between the aggregates of hydrogen-terminated diamond particles. In the above step (2), the active carbon atom on the diamond particle surface is terminated with hydrogen, and the CH stretching observed in the absorption spectrum of the powder by Fourier transform infrared spectrophotometer (FTIR) is observed in the vicinity of 2800 to 3000 cm ^−1. The method according to claim 14, wherein the height of the absorption peak attributed to is equal to or higher than the height of the absorption peak attributed to OH stretching observed in the vicinity of 3000 to 3600 cm ⁻¹ .   The method according to claim 14, wherein in the steps (1) and (2), the fine diamond powder is subjected to an oxidation treatment prior to the hydrogen termination treatment.   The method according to claim 14, wherein in the step (2), the hydrogen termination temperature is 500 ° C or higher and 1000 ° C or lower.   The method according to claim 14 or 21, wherein the hydrogen termination temperature is 600 ° C or higher and 800 ° C or lower.   The method according to claim 14, wherein the resin is a thermosetting resin.   The method according to claim 14, wherein the resin contains one selected from a phenol resin, an epoxy resin, a melamine resin, a urea resin, a urethane resin, an alkyd resin, and an unsaturated polyester.   The method according to claim 14, wherein the organic medium contains one selected from alcohols, ketones, chain hydrocarbons, cyclic hydrocarbons, and acetates. The method according to claim 14, wherein the organic medium contains one selected from lacquer thinner, urethane thinner, epoxy thinner, acrylic thinner, and melamine thinner.