JP2003105324A - Abrasive grain and method for producing the same, polishing tool and method for producing the same, grindstone for polishing and method for producing the same and polishing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide abrasive grains capable of carrying out polishing processing having an ultrahigh processing efficiency without sacrificing processed surface roughness and a polishing tool and a polishing apparatus of long life using the abrasive grains. SOLUTION: The abrasive grains are a granular porous material prepared by heat-treating secondary grains formed by making a plurality of primary grains aggregate at a temperature for forming necks in connecting points of the mutual primary grains and partially and mutually loosely binding a plurality of fine cutting edge-forming grains with formed voids. Since the cutting edge- forming grains have constitution formed by growing the primary grains during the heat treatment, processing can extremely efficiently and stably be carried out over a long period while maintaining excellent quality.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polishing tool for finishing hard and brittle materials such as silicon and glass, and metal materials such as steel and aluminum, and a method for manufacturing the same, and a method for obtaining such a polishing tool. The present invention relates to a polishing apparatus including abrasive grains and a polishing tool, and more particularly to a polishing tool having a long life for improving the quality and efficiency of processing and a manufacturing method thereof.

[0002]

2. Description of the Related Art Abrasive processing using an abrasive slurry has been used for final finishing of parts made of various hard and brittle materials such as silicon wafers and glass disks and metallic materials. This processing method, since it is easy to use fine abrasive grains, it is possible to easily obtain an excellent finished surface, and it is possible to maintain stable processing characteristics by using a large amount of abrasive slurry, It has been widely used.

However, in polishing using such an abrasive slurry, a large amount of slurry is required, and at the same time, a large amount of slurry waste liquid is discharged, so that the load on the environment is extremely high, and there is a limit to the improvement of processing efficiency. is there. For these reasons, development of fixed-abrasive machining tools capable of obtaining a finished surface that is equal to or better than the polishing finish using an abrasive slurry is being actively carried out in various fields.

Here, it is advantageous to use fine abrasive grains in order to obtain good surface roughness in the abrasive grain processing, and fine abrasive grains are also used in the fixed abrasive grain processing tool. ing. However, in order to obtain an excellent machined surface such as a mirror surface, when a fixed-abrasive machining tool having abrasive grains with a grain size of several μm or less is used, the bonding material that bonds the abrasive grains and the base material together with the workpiece. Contact occurs, and chips are accumulated between the abrasive grains to cause clogging. As a result, machining resistance increases rapidly, and in the worst case, machining becomes impossible.

Even if a means for suppressing the contact between the abrasive grain binding material and the workpiece is taken, the grain size is small and the machining efficiency is lowered. There is.

On the other hand, in order to improve the machining efficiency, it is necessary to select abrasive grains having a large grain size. In this case, although the machining efficiency is improved, the quality of the machined surface is deteriorated and it becomes difficult to obtain a mirror surface.

As a means for solving these problems, a fixed-abrasive machining tool which granulates fine abrasive grains and uses powder in the agglomerated state as abrasive grains is disclosed in Japanese Patent Laid-Open No. Hei 7-164324,
JP-A-8-155840, JP-A-9-504235
No. 2000-197807, 2000-23
7962, JP 2000-176842 A, JP 2001 A
It is proposed in the official gazette such as -129764. In these fixed-abrasive machining tools, an excellent machined surface roughness is obtained by the action of the fine abrasive grains, and at the same time, machining efficiency is improved by the agglomerated abrasive grains.

However, these techniques, which do not pay attention to the bonding force between the fine particles forming the abrasive grains, cannot meet the demand for improvement of the machining efficiency and further fixing when the machining efficiency is to be further improved. It has been found that problems such as insufficient life of the abrasive processing tool occur.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, that is, polishing work with extremely high work efficiency can be continued for a long time without sacrificing the work surface roughness. It is an object of the present invention to provide an abrasive grain, and a long-life polishing tool and polishing apparatus using such an abrasive grain.

[0010]

The inventors of the present invention further diligently studied a fixed-abrasive machining tool that granulates fine abrasive grains and uses the agglomerated powder as abrasive grains according to the above-mentioned conventional technique. As a result of overlapping, it depends on the object to be processed,
Basically, it has been found that the bonding force between the fine particles forming the abrasive grains is a very important factor. That is, in these conventional techniques, no attention has been paid to the bonding force between the fine particles constituting the aggregated abrasive grains.

Here, as a result of the use of the abrasive grains in the polishing / grinding process, the abrasive grains gradually wear and become in a flattened state. It is a processed surface.

In the case of abrasive grains made of sintered ceramics, high polishing efficiency can be obtained, but since there are no voids and it is too hard, a large scratch is newly added by processing on the surface to be processed. And deteriorate the processed surface roughness.

On the other hand, in the case of an abrasive grain composed of secondary particles formed by agglomeration of fine primary particles, a kind of cutting edge is formed by the primary particles and the space, so that high polishing quality is obtained. Is obtained.

However, in an abrasive grain composed of secondary particles formed by agglomeration of such fine primary particles, the primary particles are too fine, or the bonding between the primary particles is not controlled, resulting in high polishing. The efficiency cannot be obtained, and practical durability and life cannot be obtained.

Here, in the abrasive grains formed by aggregating fine particles, the inventors of the present invention appropriately adjust the binding force between the fine particles to gradually promote the abrasion of the abrasive grains due to processing. As a result, new cutting edges are constantly generated, high processing efficiency for the work piece, and high processing surface quality on the order of nanometers can be obtained and excellent processing characteristics can be maintained for a long time. Yes, at this time
It has been found that the wear of the abrasive grains themselves is suppressed, and as a result, the tool life can be extended.

That is, in order to solve the above-mentioned problems, the abrasive grain of the present invention has a secondary particle formed by agglomeration of a large number of primary particles having a neck at the bonding point between the primary particles. A granular porous body obtained by heating at a temperature for forming, in which a large number of fine cutting edge forming particles are loosely bonded to each other partially and forming voids, The blade-forming particles are abrasive grains formed by growing primary particles during the heat treatment.

According to such a constitution, the abrasive grain functions as a cutting edge at the time of actual use, as in claim 2, at least a portion of the machined surface of the cutting edge forming particle which is in contact with the void. , The cutting edge forming particles are worn away and fall off as the cutting edge is lost, and new cutting edge forming particles have a function of sequentially protruding to the processing surface. In addition, self-generated blades are always generated, chip removal is good, excellent quality is maintained, efficiency is extremely high, and stable machining can be performed for a long time.

A third aspect of the present invention is the abrasive grain according to the first or second aspect, wherein the compressive fracture strength is 1 MPa or more and 500 MPa or less. According to the invention of claim 3, as the abrasive grains, the abrasion of the abrasive grains themselves and the degree of detachment that occurs as the cutting edge forming particles wear away the portion that becomes the cutting edge are optimized, and it is favorable. It is possible to process with a higher efficiency while maintaining a good surface quality, and at the same time, it is possible to suppress the wear of the abrasive grains, so it is possible to make the abrasive grains with a good balance of processing efficiency, processing quality and long life,
The life of the polishing tool having such abrasive grains can be extended.

Here, the compressive fracture strength of the abrasive grains is 500MP.
When it exceeds a, scratches are likely to occur on the machined surface, which may deteriorate the quality of the machined surface. Also,
On the other hand, if the compressive fracture strength is less than 1 MPa, the binding force of the cutting edge forming particles is too weak, and sufficient polishing and grinding cannot be performed. May be extremely reduced, and the pre-machined surface of the workpiece may not be completely removed. Further, when applied to a grindstone, grinding burn is likely to occur.

Grinding burn is a phenomenon in which protrusion of abrasive grains cannot be obtained in a grinding wheel and a binder that fixes the abrasive grains comes into contact with a workpiece. At this time, normal grinding is performed. It means that the temperature of the ground surface rises and the ground surface is discolored.

According to a fourth aspect of the present invention, in the abrasive grain according to the third aspect, the compressive fracture strength is 20 MPa or more and 300 MPa.
It has the following configuration. According to the invention described in claim 4, it is possible to perform the processing with higher efficiency while maintaining the quality of the machined surface, and at the same time, it is possible to more effectively suppress the abrasion of the abrasive grains. The life of the polishing tool can be extended.

The invention according to claim 5 is the abrasive grain according to claim 1 or 2, wherein the specific surface area of the pores is 18000c.
m has a ² / cm ³ or more 700000Cm ² / cm ³ or less structure. As the abrasive grain, the wear of the abrasive grain itself and the degree of detachment that occurs as the cutting edge forming particle wears away and loses the part that becomes the cutting edge, and it is possible to process with high efficiency while maintaining good surface finish. At the same time, it is possible to suppress the wear of the abrasive grains, so that it is possible to make the abrasive grains that have a good balance of processing efficiency, processing quality and long life, and to extend the life of the polishing tool having such abrasive grains. can do.

Here, the specific pore surface area of the abrasive grains is 18,000.
When it is less than cm ² / cm ³ , scratches are likely to occur on the machined surface, which may deteriorate the quality of the machined surface. On the contrary, the pore specific surface area is 700000 cm ² / c
If it is larger than m ^3, the bonding force between the cutting edge forming particles is too weak, so sufficient polishing and grinding cannot be performed, and conversely, the abrasive grains themselves are severely worn and the processing efficiency is extremely reduced. However, there is a possibility that the pre-processed surface of the processed product cannot be completely removed. Further, when applied to a grindstone, grinding burn is likely to occur.

The invention according to claim 6 is the abrasive grain according to claim 5, wherein the pore specific surface area is 100,000 cm ² / cm ³ or more and 300,000 cm ² / cm ³ or less.
According to the invention described in claim 6, it is possible to perform the processing with higher efficiency while maintaining the high processed surface quality, and at the same time, it is possible to more effectively suppress the abrasion of the abrasive grains. The life of the polishing tool can be extended.

The invention according to claim 7 is the abrasive grain according to any one of claims 1 to 9, wherein the cutting edge forming particles have an average particle diameter of 5 μm or less. According to the invention described in claim 7, it is possible to surely obtain excellent processing quality. Here, if the average particle diameter of the cutting edge forming particles exceeds 5 μm, scratches may occur on the processed surface and the processing quality may be deteriorated, which is not preferable. Here, in order to prevent the average particle diameter of the cutting edge forming particles from exceeding 5 μm, it can be achieved by adjusting the heat treatment conditions.

Further, the invention according to claim 8 is claim 1
The abrasive grain according to any one of claims 1 to 7 has a configuration that does not include a binder for binding the cutting edge forming particles to each other.

With this structure, the cutting edge forming particles are worn away and fall off as the cutting edge portion is lost, and when new cutting edge forming particles are sequentially ejected to the machined surface, the cutting edge forming particles are formed. The amount of protrusion of particles from the binder does not become insufficient, and it avoids the occurrence of scratches due to crushing, clogging, binder residue and chip adhesion to the binder, which causes problems in processing quality. can do.

In order to obtain excellent abrasive grains as described above,
According to the method for producing abrasive grains of the present invention, a step of aggregating a large number of primary particles to obtain secondary particles as described in claim 9 and a neck is formed at the bonding points of the secondary particles with each other. Heat treatment at a temperature to grow primary particles into cutting edge-forming particles, and a large number of fine cutting edge-forming particles partially and form voids that are loosely bonded to each other and are granular porous. And a step of obtaining abrasive grains composed of a body.

According to the method for producing abrasive grains of the present invention as described above, the abrasive grains obtained by the two steps as described above are used as the actual abrasive grains as described in claim 2. At least a portion of the cutting edge forming particles in the processed surface which is in contact with the void functions as a cutting edge, and the cutting edge forming particles are worn off and fall off as the cutting edge is lost, and new cutting edge forming particles are formed. It has a function of sequentially protruding to the machined surface, during polishing and grinding, a self-generated blade is always formed on the abrasive grains, the removal of chips is also good, and excellent efficiency is maintained and extremely efficient, and It is possible to perform processing stably for a long time.

At this time, it is desirable to perform the heat treatment under the condition that the average particle diameter of the cutting edge forming particles formed as described in claim 10 is 5 μm or less. That is, when the average particle diameter of the cutting edge forming particles exceeds 5 μm, scratches may occur on the processed surface and the processing quality may be deteriorated, which is not preferable.

A polishing tool having the abrasive grains according to any one of claims 1 to 7 on the polishing surface, like the polishing tool according to claim 11, is an excellent polishing tool according to the present invention. With the granules, excellent quality can be maintained, the efficiency is extremely high, and the processing can be stably performed for a long time.

A polishing tool according to a twelfth aspect is the polishing tool according to the eleventh aspect, wherein abrasive grains are exposed on the surface of the polishing surface of the polishing tool. With such a configuration, it is possible to prevent deterioration in processing quality due to the abrasive grains or the binder that fixes the abrasive grains and the base material that supports the abrasive grains. Here, as the binder, one or more of resin, ceramic, and metal can be used, and, for example, a ceramic precursor may be used to obtain a ceramic by subsequent heat treatment.

The polishing tool according to claim 13 is the polishing tool according to claim 11 or 12, wherein the polishing tool is any one of a polishing film, a polishing cloth and a polishing grindstone. And Since the polishing tool is any one of the polishing film, the polishing cloth, and the polishing grindstone as described above, it is possible to obtain high processing efficiency and high quality with the abrasive grains according to any one of claims 1 to 7. The effect that enables processing can be exerted particularly effectively.

When the polishing film is used, the effect of the above-mentioned abrasive grains can be sufficiently obtained, and the polishing film itself is an inexpensive polishing tool. It is possible to perform polishing processing at a relatively low cost.

In the case of a polishing cloth, the effect of the above-mentioned abrasive grains can be sufficiently obtained, and the polishing cloth can be used as a tool in a conventional polishing machine or lapping machine by replacing it with a surface plate. Unlike the polishing film, new abrasive grains appear on the surface of the polishing tool as it wears, so that it can be used for a long time. Therefore, the workpiece can be efficiently
The finished surface has excellent quality, and the tool life is long, so the tool cost is low, and at the same time, the burden on the operator such as tool change can be reduced.

Further, by applying it to the grindstone by applying it to the grindstone for polishing, it is possible to stably and efficiently finish the workpiece with excellent work surface quality without causing grinding burn during polishing and grinding. .

The polishing tool according to claim 14 is the polishing tool according to claim 13, wherein the polishing tool is a polishing film, and a thickness of a binder layer for fixing the abrasive grains to the base film. Is smaller than the maximum diameter of the abrasive grains. With such a configuration, it is possible to prevent the polishing quality from being deteriorated due to the binder coming into contact with the surface to be polished, and to guarantee the protrusion amount of the abrasive grains.

A polishing tool according to a fifteenth aspect is the polishing tool according to any one of the eleventh to fourteenth aspects, wherein the content rate of the abrasive grains in the portion having the abrasive grains is 5
It is characterized in that it is from 90% by volume to 90% by volume. With such a configuration, it becomes possible to obtain excellent processed surface quality with high efficiency. If the content of the abrasive grains is less than 5% by volume, the effect of addition may not be sufficiently obtained. On the other hand, if the content exceeds 90% by volume, the amount of the binder in the polishing tool is too small, and The holding strength is remarkably reduced and it cannot be used as a polishing tool.

A polishing tool manufacturing method according to claim 16 is
A step of aggregating a large number of primary particles to obtain secondary particles, and heat-treating the secondary particles at a temperature at which a neck is formed at a binding point between the primary particles to grow the primary particles to form a cutting edge forming particle. And a large number of fine cutting edge forming particles partially, and
The method includes the steps of forming voids to obtain abrasive grains composed of granular porous bodies loosely bonded to each other, and fixing the abrasive grains to a base material. With such a configuration, it is possible to easily obtain a long-life polishing tool that can perform polishing with extremely high efficiency while maintaining excellent quality.

Further, in the method for manufacturing an abrasive tool according to claim 16, as described in claim 17, in the step of fixing the abrasive grains to the base material, at least one selected from resins, ceramics and metals. By using the above binder, it is possible to obtain a polishing tool satisfying the required heat resistance and strength. The surface of the abrasive grains used at this time may be modified to improve the adhesion with the binder.

The fixing method can be carried out, for example, by applying a mixture of a binder and abrasive grains to the base material using, for example, a wire bar coater, a gravure coater, a reverse roll coater or a knife coater.

Further, in the polishing tool manufacturing method of the seventeenth aspect, as in the eighteenth aspect, in the step of fixing the abrasive grains to the base material, the abrasive grains are fixed to the base material together with the reinforcing material. This makes it possible to obtain a polishing tool having a long life. Here, as the reinforcing material, as described in claim 19,
Examples thereof include metal powder, carbon fiber, inorganic fiber such as glass fiber, organic fiber such as polyacrylonitrile fiber, and metal fiber. When fibers are used, they can be used as chopped fibers, milled fibers or the like, if necessary. Further, the surface of these fibers can be further modified to improve the adhesion with the binder. In addition to the above, various whiskers can be used as the reinforcing material.

The method for manufacturing a polishing tool according to a twentieth aspect is the method for manufacturing a polishing tool according to any one of the sixteenth to nineteenth aspects, wherein the polishing tool is a polishing film or a polishing cloth. Characterize.

Further, in the method for producing a polishing grindstone according to a twenty-first aspect, a step of aggregating a large number of primary particles to obtain secondary particles, a neck is formed at the connecting points of the secondary particles with each other. Heat treatment at a certain temperature to grow a plurality of primary particles to form cutting edge-forming particles, and a large number of fine cutting edge-forming particles partially and form voids and are loosely bonded to each other. A step of forming abrasive particles composed of a porous body, a step of mixing or kneading the binder for binding the abrasive particles and the abrasive particles to obtain an abrasive particle mixed material, and molding and polishing the abrasive particle mixed material It is a method for manufacturing a polishing grindstone having a step of forming a polishing grindstone, and by such a manufacturing method, it is possible to easily obtain a polishing grindstone capable of performing processing with extremely high efficiency while maintaining excellent quality. Here, as the binder, one or more of resin, ceramic, and metal can be used, and, for example, a ceramic precursor may be used to obtain a ceramic by subsequent heat treatment.

Further, in the method for producing a polishing grindstone according to the twenty-second aspect, as described in the twenty-first aspect, the abrasive grains and a binding material for binding the abrasive grains are mixed or kneaded to form an abrasive grain mixed material. In the step of obtaining, it is possible to improve rigidity and wear resistance by adding a reinforcing material, and it is possible to obtain a polishing grindstone having a long life. At this time, as described in claim 23, as the reinforcing material,
Examples thereof include organic fibers, inorganic fibers and metal fibers, and these fibers can be used in an appropriate length such as chopped fiber or milled fiber, if necessary. Further, the surface of these fibers can be further modified to improve the adhesion with the binder. Further, various whiskers or the like can be used as the reinforcing material.
Furthermore, the surface of these reinforcing materials can be modified to improve the adhesion with the binder.

A polishing apparatus according to a twenty-fourth aspect has the polishing tool according to any one of the eleventh to fifteenth aspects. Such a polishing apparatus has high polishing efficiency and polishing quality, and since the polishing tool has a long life, it is possible to replace it with little labor. Such a polishing tool is capable of high-quality processing with high processing efficiency and has a long life.

[0047]

BEST MODE FOR CARRYING OUT THE INVENTION The abrasive grains of the present invention are obtained by heat-treating secondary particles formed by aggregating a large number of primary particles at a temperature at which a neck is formed at a bonding point between primary particles. A large number of fine cutting edge forming particles are partially, and form a void, a granular porous body formed by loosely bonding to each other, and the cutting edge forming particles grow primary particles during the heat treatment. It is an abrasive grain formed by.

As described above, unlike the conventional abrasive grains composed of secondary particles formed by simply aggregating fine primary particles,
A large number of fine cutting edge-forming particles are partially formed, and form a void, while maintaining the structure of a granular porous body loosely bonded to each other, but the primary particles in the conventional abrasive grains Compared with the bond of No. 1, since the bond is strong because the neck is formed in the bonding portion of the cutting edge forming particles formed by the growth of the primary particles by the heat treatment, the polishing efficiency and the polishing quality are maintained, but the long The use of time can be enabled.

The cutting edge forming particles in the present invention are particles in which primary particles in secondary particles formed by aggregating a large number of primary particles are grown by heat treatment, and at least a part thereof is polished or ground. Particles that exert a working action on a work piece as a cutting edge on the work piece when used for.

Further, according to the heat treatment for growing the primary particles as described above, not only the primary particles grow due to the mass transfer of the substance constituting the particles, but also the binding points between the particles form the substance forming the particles. It becomes thicker due to the mass transfer, and becomes a smooth curved surface without discontinuities, and becomes a so-called “neck” shape that is constricted in a one-leaf hyperboloid shape (hand drum shape). Regarding the growth of primary particles and the formation of “neck” due to the mass transfer during the heat treatment, “2. of“ Ceramic material technology compilation ”issued by Industrial Technology Center Co., Ltd. 3 Mass Transfer Mechanisms and Sintering Models ".

As described above, in the present invention, since the cutting edge forming particles are bonded to each other by the substance itself constituting the cutting edge forming particles, no binder is contained as abrasive grains, and as a result, the cutting edge forming particles are worn. And as it falls off as it loses the part that becomes the cutting edge, new cutting edge forming particles are sequentially ejected to the processing surface, so the binder of the cutting edge forming particles that occurs when the abrasive grains are formed using the binder In addition, it is possible to avoid problems such as insufficient amount of protrusion from the machine, scratches due to crushing, clogging, binder remaining and chip adherence to the binder, etc. it can.

However, when a large number of primary particles are aggregated with each other to form secondary particles, it is preferable to use a binder made of, for example, an organic substance, which is completely eliminated by heat treatment such as oxidation, decomposition or evaporation. This is possible, and in that case, the above-mentioned inconvenience is avoided because the binder does not remain when used as abrasive grains.

By thus forming the neck-like bonding points between the particles, the strength of the bonding between the cutting edge forming particles is strengthened, and as a result, together with the growth of the particles themselves, a high processing efficiency and , While being capable of high-quality processing,
It is possible to obtain abrasive grains that can be processed for a long time.

In the present invention, the raw material forming the primary particles is a material in which the substance forming the particles is mass-transferred and grows by the heat treatment as described above, and has physical properties that can be accepted when used as abrasive grains. Any hard inorganic material can be used, such as silica, ceria, cubic boron nitride (cB
N), alumina, silicon carbide, zirconium oxide, etc., and the average primary particle size is 5 μm.
It is desirable to use the following.

The secondary particles in the present invention are aggregates composed of many fine primary particles. As a method for obtaining such secondary particles by aggregating a large number of fine primary particles with each other, a spray dryer (generally 1 μm to 300 μm) is used.
Sizes up to μm are obtainable. When the particle size distribution is not sharp, a classification process is added), a sol-gel method, a freeze-drying method in which a solvent is used in combination, a solvent drying method, and the like.
Further, as a method utilizing the thermal decomposition and solid phase reaction of a solid, or a method of forming from a gas, an evaporation-aggregation method, a gas phase decomposition method, and other gas phase reactions can be used.

The secondary particles obtained as described above are heat-treated to grow the primary particles in the secondary particles. The heat treatment in the present invention needs to be performed under the conditions (temperature, time) in which the primary particles among the secondary particles formed by aggregating a large number of primary particles as described above grow.

The condition of the heat treatment is appropriately selected depending on the substance constituting the primary particles, but usually the heat treatment is 10
Select a temperature that will finish within minutes to a few hours. If the heat treatment time is too long, it will be difficult to control, and it will sinter like normal ceramic abrasive grains. If the result is the same as the result of binding, the effect of the present invention cannot be obtained.

Here, the heat treatment test was conducted in advance at several different temperatures and times, and the internal structure of the treated particles was observed with an electron microscope or the like to confirm that the bonding points between the cutting edge forming particles were not observed. A number of fine cutting edge forming particles within a range of conditions (indicating that primary particles have grown) in which a so-called “neck” shape is formed, which is a smooth curved surface with no continuous points and is constricted in a one-leaf hyperboloid shape. Partially and forming a void,
A condition is searched for within a range in which the granular porous body structure loosely bonded to each other is maintained.

These temperatures and times vary greatly depending on the material, but in the materials exemplified above, the temperature is generally 500 to 1600 ° C.
Several minutes to 24 hours. At this time, it is also possible to pressurize if necessary.

However, if the cutting edge-forming particles constituting the abrasive grains grow and become too large, the above balance may be lost and the effects of the present invention may not be obtained. It is desirable to carry out under the condition that the average grain size of the formed grains is 5 μm or less.

In the above heat treatment, the abrasive grains obtained have a compressive fracture strength of 1 MPa or more and 500 MPa or less, or a pore specific surface area of 18000 cm ² / cm ^3.
It is preferable to carry out under the condition of not less than 700,000 cm ² / cm ³ . At this time, it is possible to polish high-processed surface quality with even higher efficiency, and at the same time, it is possible to suppress wear of the abrasive grains, and it is possible to use the abrasive tool having the abrasive grains for a longer period of time, which makes it difficult to replace the abrasive tool. The cost required for exchanging the polishing tool can be reduced and the cost can be reduced.

[0062]

EXAMPLES The abrasive grains of the present invention will be specifically described below with reference to examples. However, the present invention is not limited to these examples, and various modifications can be carried out without departing from the gist of the present invention.

In the present invention, the average particle size is LA-92, a laser diffraction / scattering particle size distribution analyzer manufactured by Horiba, Ltd.
No. 0 was used to perform the dry process, and the particle size at the frequency cumulative 50% was used as the average particle size (usually called the median size).

The compressive fracture strength test was reported by Hiramatsu, Oka and Kiyama (Journal of the Japan Mining Industry, 81, 1024 (196).
5)) Shimadzu Corporation's micro compression tester MC
It was performed using TM500PC.

As a test condition, a test load is 10 to 100.
0 mN, the load speed is 0.446 mN / sec, the granules to be measured are compressed using a flat indenter, and the strength when the granules are broken by the compression is measured. The relationship between the compression displacement and the load at this time is shown as a model in FIG. The compressive fracture strength was calculated by reading the load value at the curved refraction part in the circle within the broken line in FIG.

On the other hand, the evaluation of the surface roughness of the machined surface was carried out using a foam Talysurf S4C manufactured by Thera Hopson. Further, the specific surface area of the pores in the present invention is BE measured by adsorption and desorption of nitrogen gas at a relative pressure of 0.3 by the BET one-point method.
The value obtained by multiplying the T specific surface area by the density of the material forming the abrasive grains was used.

Example 1 Ultrafine zirconium oxide (ZrO ₂ ) powder having a particle size of 50 to 60 nm was slurried by adding water (aqueous binder, for example, polyvinyl alcohol-water mixture may be used). Is sprayed with a spray drier and the average particle size of the secondary particles α is 50 μm.
Got The compressive fracture strength of this secondary particle α is 0.47MP
It was a. Whole scanning electron microscope (S
EM photograph and partially enlarged scanning electron microscope (SE
M) Photographs are shown in FIGS. 2 and 3.

The secondary particles α were heat-treated in an electric furnace.
By this heat treatment, the polyvinyl alcohol used as the binder during the formation of the secondary particles as described above is completely removed.

According to the conditions examined in advance, the heat treatment temperature and the heat treatment time were adjusted so that the internal particles inside the porous granules functioning as the cutting edge forming particles when used as abrasive grains were 5 μm or less. FIG. 4 shows a partially enlarged SEM photograph (same magnification as in FIG. 3) of an example of the porous particles (abrasive particles β) made of zirconium oxide that have been subjected to heat treatment under appropriate conditions.

As shown in FIG. 4, the porous particles that function as cutting edge forming particles when used as abrasive grains are clearly larger than the primary particles shown in FIG. 3, and the bonding between the particles is one leaf. It can be confirmed that it has a so-called “neck” shape that is constricted in a curved shape, and that a large number of fine cutting edge forming particles partially and form voids and are loosely bonded to each other. . When the heat treatment is performed for an excessively long time or an excessively high temperature, the primary particles are completely bonded to each other to form a substantially perfect sintered body.

The compression fracture strength thus obtained was 92.
Abrasive grain β of 6 MPa having an average particle size of 50 μm according to the present invention
Was mixed with a liquid urethane resin so that the volume ratio of the particles was 35% by volume, and methyl ethyl ketone was further added as a solvent to adjust the solution viscosity.
A mixture was prepared by mixing and stirring for about a minute. The stirring was carried out at room temperature and at a rotation speed of 50 rpm so as not to destroy the abrasive grains.

This mixture was applied to a substrate (P with a thickness of about 75 μm).
It was applied to the ET film using a wire bar coater and then dried in a constant temperature bath kept at 60 ° C. for 1 hour to obtain a polishing film A as a polishing tool.

The maximum thickness of the obtained coating layer (portion having abrasive grains) is almost equal to the maximum diameter of the abrasive grains according to the present invention having a particle size distribution (using a solvent as described above). This makes it easy to reduce the thickness of the binder layer). The polishing film A thus produced was attached to a lapping plate, and an optical glass disk (borosilicate crown glass (BK7 equivalent product)) having a diameter of 30 mm adjusted to have a maximum height roughness Ry of 2 μm was processed. (Processing conditions: surface plate rotation speed 60 rpm, processing pressure 46 kPa), 2
Maximum height roughness Ry of 30 nm without scratches in a minute
The following mirror surface was obtained.

Further, even if 20 similar glass disks were subsequently processed under the same conditions, there was almost no decrease in the processing efficiency or the processed surface roughness. Here, an enlarged photograph of the surface of the glass disk before processing is shown in FIG. 5, a surface roughness measurement result (chart) at that time is shown in FIG. 6, and an enlarged photograph of the surface after processing (the same magnification as in FIG. 5) is used. 7 and FIG. 8 show the surface roughness measurement results. From these, it can be seen that the unevenness that existed before the processing was almost eliminated after the processing and became a mirror surface.

Further, the abrasion condition of the abrasive grains on the polishing film A after processing ten glass disks was examined. The state of the surface is shown in FIG. It can be seen from FIG. 9 that since the cutting blade forming particles have an appropriate bonding force, the abrasion gradually progresses as the processing progresses, and the abrasive grains are not largely damaged or dropped from the base material.

[Comparative Examples 1 and 2] Secondary particles α in Example 1
As in the production of abrasive grains β, but with the heat treatment conditions changed.
And has a compressive fracture strength of 0.6 MPa and a pore specific surface area
Is 1,000,000 cm ²/ Cm³Abrasive grain γ and compression fracture
Breaking strength is 613 MPa and pore specific surface area is 3000 cm²
/ Cm³Abrasive grain δ was obtained. These average particle sizes are both 5
It was 0 μm.

Observation of these abrasive grains γ and δ with a scanning electron microscope revealed that the compressive fracture strength was 0.6 MPa.
No formation of "neck" was observed with the abrasive grain δ of No. 1, and it was found that the heat treatment was insufficient and the primary particles did not grow. On the other hand, in the case of the abrasive grain δ having a compressive fracture strength of 613 MPa, a large number of fine cutting edge forming particles partially and form voids, and there is no structure in which they are loosely bonded to each other, are almost completely sintered bodies. Was becoming.

Polishing film B (compressive breaking strength of abrasive grains γ: 0.6 MPa, using the same method as described above for polishing film A) using these two types of abrasive grains γ or δ, respectively.
Comparative Example 1) and polishing film C (compressive fracture strength of abrasive grains δ:
613 MPa, Comparative Example 2) was prepared. Each of these polishing films B and C was similarly attached to the above lapping machine, and processing was performed on the BK7 optical glass disk adjusted so that the maximum height roughness Ry was 2 μm under the same processing conditions. The polishing film B was processed for 20 minutes, but the maximum height roughness Ry could only reach 1.275 μm.

The secondary particles α which have not been heat-treated
A similar processing test was carried out using a polishing film prepared by using (compressive fracture strength 0.47 MPa). As a result, the processing efficiency was lower than that of the polishing film B, and the pre-processed surface could not be improved.

FIG. 10 shows an enlarged photograph of the surface of the glass disc before processing before processing, FIG. 11 shows the result of surface roughness measurement, and enlarged photograph of the surface after processing for 20 minutes. 10) and the surface roughness measurement results are shown in FIGS. 12 and 13, respectively. FIG. 14 shows the state of the abrasive grains on the polishing film B after processing and use.

From these results, although the surface roughness of the glass disk was slightly improved by polishing with the polishing film B for 20 minutes, the abrasion of the abrasive grains was severe (FIG. 14).
It can be seen that the pre-processed surface of the glass disc has not been completely removed.

On the other hand, when the polishing film C is used, since the abrasive grains which are completely sintered bodies in which the primary particles are completely bonded to each other are used, a large scratch is newly formed on the surface of the glass disk by processing the surface in reverse. And the maximum height roughness Ry was deteriorated to 2.7228 μm (FIG. 15).
Fig. 16 shows an enlarged photograph of the surface (scratches are visible), and Fig. 16 shows the surface roughness measurement results (the existence of scratches is confirmed).
Then, the abrasive grains themselves were not much worn, and the tip portion was not flattened by observation with a microscope.

Similarly, polishing films having abrasive grains of various compressive fracture strength were prepared, and the relationship between the compressive fracture strength and the machined surface roughness (symbol: □) and the machining efficiency (symbol: ◇) was investigated. . Results are shown in FIG. The machining efficiency on the vertical axis in FIG. 17 relatively indicates the grinding amount per unit time, and the higher the machining efficiency in the graph, the higher the machining efficiency.

From FIG. 17, when the compressive fracture strength is too small (compressive fracture strength: less than 1 MPa), that is, when the binding force of the cutting edge forming particles is too weak, the machining efficiency is low, and the abrasive grains themselves are not affected by the machining pressure. Since the pre-processed surface cannot be completely removed due to the progress of destruction, the processed surface roughness is hardly improved. On the other hand, if the compressive fracture strength is too high, for example,
In the case of an almost completely sintered body (compressive fracture strength: 613 MPa), the processing efficiency was remarkably increased, but on the other hand, the quality of the processed surface was also greatly deteriorated. As described above, only the abrasive grain according to the present invention having an appropriate binding force for the cutting edge forming particles was able to achieve high processing surface quality (mirror surface) with high efficiency. At that time, it was also found that abrasion of the abrasive grains themselves was suppressed and the life of the polishing tool was extended.

FIG. 18 shows a diagram in which the relationship between the specific surface area of pores, which is a parameter representing the internal structure of the abrasive grains, and the working efficiency was examined for the abrasive grains having various compressive fracture strengths shown in FIG. Here, the pore specific surface area is different from the normal specific surface area (the unit is “cm ² / g” or “m ² / g” etc.), and the influence due to the difference in the specific gravity of the material is excluded.
This is a parameter that shows the difference in internal structure more significantly. Further, the machining efficiency on the vertical axis in FIG. 18 indicates the relative amount of grinding per unit time, and the higher the machining efficiency in the graph, the higher the machining efficiency.

From FIG. 18, the effect of heat treatment is not sufficiently exerted and the pore specific surface area is too large (pore specific surface area:
(More than 700,000 cm ² / cm ³ ), that is, when the binding force of the cutting edge forming particles is too weak, the machining efficiency is low, and since the abrasive grains themselves are destroyed by the machining pressure, the pre-machined surface cannot be completely removed. Since it does not exist, the machined surface roughness is hardly improved.
On the other hand, the pore specific surface area is too small, a large number of fine cutting edge forming particles are partially, and form a void, the structure loosely bonded to each other is lost, for example,
Boho perfect sintered body (pore specific surface area: 5000 cm ² / c
In the case of m ³ or less), the machining efficiency was remarkably increased, but on the other hand, the quality of the machined surface was significantly deteriorated. As described above, only the abrasive grain according to the present invention having an appropriate cutting edge forming particle binding force and a specific structure was able to achieve a high processed surface quality (mirror surface) with high efficiency. At that time, it was also found that abrasion of the abrasive grains themselves was suppressed and the life of the polishing tool was extended.

[Example 2] Silica abrasive grains having a primary particle diameter (average particle diameter 50 nm) of colloidal silica were
The silica powder thus obtained was agglomerated by the sol-gel method so that the average particle diameter was 30 μm, and the obtained silica powder was dried to remove water and organic solvent contained in the pores to obtain secondary particles ε.

With respect to the secondary particles ε thus obtained,
After heat treatment under various conditions, scanning electron microscope observation was carried out, and from among these, many fine cutting edge forming particles partially and form voids and loosely bound to each other. An abrasive grain ζ according to the present invention is obtained, which is a granular porous body having the following shape, and the cutting edge forming particles are granular porous particles formed by growing primary particles during the heat treatment. The compressive fracture strength of the abrasive grains ζ was 124.2 MPa, and the size of the cutting edge forming particles was 1.2 μm.

The obtained abrasive grain ζ was mixed with a polyurethane resin so that the volume ratio was 35% by volume, and the copper powder (reinforcing material) having an average particle size of 3 μm was 15% by volume. Then, mix and stir at 60 rpm for 15 minutes with a stirrer,
A mixture was obtained (at this time, if necessary, a foaming agent for forming closed cells can be added).

This mixture was poured into a circular mold (450 mmΦ) and then cured by heat treatment at 120 ° C. for 10 hours to obtain a polishing cloth. The obtained polishing cloth was cut into a predetermined size and attached to a surface plate, and a silicon wafer having a diameter of 30 mm which had been previously ground with a grindstone corresponding to # 2000 was polished.

As a result, it was possible to obtain a mirror surface having a maximum processed surface height roughness Ry of 20 nm or less without scratching after processing for 10 minutes. Further, even when 20 silicon wafers were subsequently polished, no reduction in processing efficiency or processed surface roughness was observed.

Here, an example in which the polishing cloth according to the present invention used in Example 2 is attached to a polishing apparatus for silicon processing, which is a polishing apparatus, is schematically shown in FIG. Reference numeral 1 in the drawing denotes a silicon wafer which is a workpiece, and the silicon wafer 1 is attached to the rotating part 10 and is rotated by the rotation of the rotating part 10.
The polishing cloth of the present invention fixed on the surface plate 20 (the polishing film may be fixed instead of the polishing cloth) is brought into contact with the lower surface of the polishing cloth, and the lower surface thereof is polished. In addition,
Since the surface plate 20 also rotates, the entire lower surface of the silicon wafer 1 is uniformly polished.

[Example 3] The above-mentioned secondary particles ε were subjected to heat treatment under the conditions different from those of Example 2 to obtain a compressive fracture strength of 18.5 MPa and a size of cutting edge forming particles of 0. ．
A study was made on a 2 μm silica abrasive grain as a polishing cloth.

A polishing cloth was produced in the same manner as in Example 2 by using the silica abrasive grains, and a silicon wafer processing test was conducted using the polishing cloth in the same manner. As a result, it was possible to obtain a mirror surface with a maximum surface roughness Ry of 20 nm or less in a processing time of 15 minutes, but when the processing was continued, the processing efficiency gradually decreased, and the number of processed sheets was 5 Although the processed surface roughness was the same as that at the start, the processing efficiency decreased by about 30%, and the processing was impossible after the 15th sheet.

Example 4 The same average particle size as used in Example 2 above, 30 μm, and compressive rupture strength, 124.2 MP.
so that the volume ratio of the abrasive grains according to the present invention of (a) is finally 45% by volume, and that the nickel powder (reinforcing material) having an average particle size of 3 μm is finally 15% by volume. The mixture was mixed with a phenol resin and mixed with a stirrer at 60 rpm for 15 minutes to obtain a mixture. Put this mixture in the mold,
Curing treatment was applied at about 150 ° C. for about 5 hours while applying pressure to obtain a grinding stone.

The polishing grindstone thus obtained was mounted on an in-feed grinder on the vertical axis, and a silicon wafer having a lapping finish was ground and processed, and as a result, the maximum height roughness Ry of the machined surface was found in one minute of machining time. A mirror surface of 30 nm or less could be obtained. Further, even if 20 silicon wafers were subsequently ground, no grinding burn occurred, and no reduction in processing efficiency or surface roughness was observed.

[Example 5] A polishing grindstone was produced in the same manner as in Example 4 except that the abrasive grains according to the present invention having the same compressive fracture strength of 18.5 MPa as those used in Example 3 were used. A silicon wafer grinding test was performed.
As a result, the machining surface maximum height roughness R
Although a mirror surface with y of 30 nm or less could be obtained, when the processing was continued, grinding burn occurred on the wafer surface with 10 processed sheets.

[0098]

As described above, in the abrasive grain of the present invention, the secondary particles formed by aggregating a large number of primary particles are heat-treated at a temperature at which a neck is formed at the bonding point between the primary particles. A large number of fine cutting edge-forming particles partially obtained, and
Abrasive grains having a structure in which voids are formed and are loosely bonded to each other, and the cutting edge forming particles are formed by growing primary particles during the heat treatment. At the time of use as, at least the portion of the cutting edge forming particles in contact with the void functioning as a cutting edge functions as a cutting edge, and the cutting edge forming particles are worn away and fall off as the cutting edge is lost. Since various cutting edge forming particles are sequentially projected to the processed surface and the binding force between cutting edge forming particles is optimized, excellent quality is maintained and extremely efficient, and stable for a long time. Can be processed.

Further, the polishing tool of the present invention is a polishing tool capable of high-efficiency and high-quality processing and having a long life. Further, the polishing apparatus of the present invention has high polishing efficiency and polishing quality, and has a long life of the polishing tool.

Further, according to the method for producing abrasive grains of the present invention,
During polishing and grinding, self-developing blades are always formed on the abrasive grains,
The removal of chips is also good, and it is possible to reliably and reliably obtain abrasive grains that can be machined extremely efficiently while maintaining excellent quality.

Further, according to the method for manufacturing a polishing tool of the present invention, it is possible to obtain a polishing tool having a long life and capable of performing processing with extremely high efficiency while maintaining excellent quality. Further, according to the method for manufacturing a polishing grindstone of the present invention, it is possible to obtain a polishing grindstone capable of maintaining excellent quality and performing processing with extremely high efficiency.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a relationship between a load and a compressive displacement in a compressive fracture strength test of abrasive grains.

FIG. 2 is a scanning electron microscope (SEM) photograph of secondary particles (a diagram showing the whole).

FIG. 3 is a scanning electron microscope (SEM) photograph of secondary particles (partially enlarged (before heat treatment)).

FIG. 4 is a scanning electron microscope (SE) of abrasive grains according to the present invention.
M) Photograph (a partially enlarged image (after heat treatment)).

5 is an enlarged photograph of the surface of the glass disk before polishing in Example 1. FIG.

FIG. 6 is a chart showing the results of measuring the surface roughness of the glass disk surface before polishing in Example 1.

FIG. 7 is an enlarged photograph of the glass disk surface after polishing in Example 1.

8 is a chart showing the results of measuring the surface roughness of the glass disk surface after polishing in Example 1. FIG.

FIG. 9 is an enlarged photograph showing the state of abrasive grains on the surface of the polishing film after polishing in Example 1.

10 is an enlarged photograph of the surface of the glass disk before polishing in Comparative Example 1. FIG.

11 is a chart showing the results of measuring the surface roughness of the glass disk surface before polishing in Comparative Example 1. FIG.

12 is an enlarged photograph of the surface of the glass disk after polishing in Comparative Example 1. FIG.

13 is a chart showing the results of measuring the surface roughness of the glass disk surface after polishing in Comparative Example 1. FIG.

FIG. 14 is an enlarged photograph showing the state of abrasive grains on the surface of a polishing film after polishing in Comparative Example 1.

15 is an enlarged photograph of the surface of the glass disk after polishing in Comparative Example 2. FIG.

16 is a chart showing the results of measuring the surface roughness of the glass disk surface after polishing in Comparative Example 2. FIG.

FIG. 17 is a diagram showing the relationship between the compressive fracture strength of abrasive grains, the machined surface roughness, and the machining efficiency in a polishing film having abrasive grains of various compressive fracture strength.

FIG. 18 is a graph showing the relationship between the specific pore surface area of the abrasive grains, the machined surface roughness, and the machining efficiency in the polishing film having the abrasive grains having various compressive fracture strengths.

FIG. 19 is a diagram showing an example of a silicon processing polishing apparatus provided with a polishing grindstone having abrasive grains according to the present invention.

[Explanation of symbols]

1 Silicon wafer 2 Polishing cloth (or polishing film) 10 rotating parts 20 surface plate

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B24D 3/02 310 B24D 3/02 310E 3/06 3/06 Z 3/14 3/14 3/28 3 / 28 11/00 11/00 AF term (reference) 3C063 AA02 AB05 AB07 BB01 BB02 BB03 BB04 BB14 BC02 BC03 BC05 BD08 BG07 BG08 CC17 EE10 FF20 FF22 FF23

Claims (24)

[Claims] 1. A large number of fine cutting edge forming particles obtained by heat-treating secondary particles formed by agglomeration of a large number of primary particles at a temperature at which a neck is formed at a bonding point between primary particles. Particulate and porous particles that are loosely bonded to each other and form voids, and the cutting edge forming particles are formed by growing primary particles during the heat treatment. Abrasive grain characterized by. 2. When used as an abrasive grain, at least a portion of the cutting edge forming particle in contact with the void on the processing surface functions as a cutting edge, and the cutting edge forming particle is abraded and loses a cutting edge portion. The abrasive grains according to claim 1, wherein the abrasive grains are removed in accordance with the above, and new cutting edge forming particles are sequentially projected to the processed surface. 3. The compressive fracture strength is 1 MPa or more and 500 MP.
It is a or less, Claim 1 or Claim 2 characterized by the above-mentioned.
Abrasive grain described in. 4. The compressive fracture strength is 20 MPa or more and 30.
It is 0 MPa or less, The abrasive grain of Claim 3 characterized by the above-mentioned. 5. A pore specific surface area of 18000 cm ² / cm ³
It is above 700,000 cm ² / cm ^{3 and} below, The abrasive grain according to claim 1 or claim 2 characterized in that. 6. The specific surface area of the pores is 100,000 cm ²
/ Cm ³ or more and 300,000 cm ² / cm ³ or less, the abrasive grain according to claim 5. 7. The abrasive grain according to claim 1, wherein the cutting edge forming particles have an average particle diameter of 5 μm or less. 8. The abrasive grain according to any one of claims 1 to 7, which does not contain a binder for binding the cutting edge forming particles to each other. 9. A step of aggregating a large number of primary particles to obtain secondary particles, and heating the secondary particles at a temperature at which a neck is formed at a bonding point between the primary particles to grow the primary particles. As the cutting edge forming particles, and a large number of fine cutting edge forming particles partially and form voids to obtain abrasive grains composed of a granular porous body loosely bonded to each other. A method for producing abrasive grains, characterized by: 10. The method for producing abrasive grains according to claim 9, wherein the cutting edge forming particles formed above have an average particle diameter of 5 μm or less. 11. A polishing tool having a polishing surface having the abrasive grains according to any one of claims 1 to 7. 12. The polishing tool according to claim 11, wherein abrasive grains are exposed on the surface of the polishing surface of the polishing tool. 13. The polishing tool according to claim 11 or 12, wherein the polishing tool is any one of a polishing film, a polishing cloth and a polishing grindstone. 14. The polishing tool is a polishing film,
The polishing tool according to claim 13, wherein the thickness of the binder layer for fixing the abrasive grains to the base film is smaller than the maximum diameter of the abrasive grains. 15. The content of the abrasive grains in a portion having abrasive grains of the polishing tool is 5% by volume or more and 90% by volume or less, according to any one of claims 11 to 14. Polishing tool. 16. A step of aggregating a large number of primary particles to obtain secondary particles, and heat-treating the secondary particles at a temperature at which a neck is formed at a bonding point between the primary particles to grow the primary particles. As a cutting edge forming particle, a step of obtaining an abrasive grain consisting of a granular porous body in which a large number of fine cutting edge forming particles are partially and form voids and are loosely bonded to each other. And a step of fixing the same to a base material. 17. The method of manufacturing an abrasive tool according to claim 16, wherein at least one binder selected from resins, ceramics and metals is used in the step of fixing the abrasive grains to the base material. 18. The method for manufacturing a polishing tool according to claim 17, wherein in the step of fixing the abrasive grains to the base material, the abrasive grains are fixed to the base material together with a reinforcing material. 19. The reinforcing material is metal powder, organic fiber,
The method for manufacturing a polishing tool according to claim 18, wherein the polishing tool is one or more selected from inorganic fibers and metal fibers. 20. The polishing tool according to claim 16, wherein the polishing tool is a polishing film or a polishing cloth.
9. The method for manufacturing a polishing tool according to any one of 9 above. 21. A step of aggregating a large number of primary particles to obtain secondary particles, wherein the secondary particles are heated at a temperature at which a neck is formed at a bonding point between the primary particles to grow a plurality of primary particles. And cutting edge forming particles, a large number of fine cutting edge forming particles partially, forming a void, to form an abrasive grain consisting of a granular porous body loosely bonded to each other, the abrasive Polishing characterized by including a step of mixing or kneading a binder for binding grains and the abrasive grains to obtain an abrasive grain mixed material, and a step of molding the abrasive grain mixed material into a grinding stone Method of manufacturing whetstone. 22. A strengthening agent is added in the step of mixing or kneading the abrasive grains and a binding material for binding the abrasive grains to obtain an abrasive grain mixed material.
A method for producing a grinding wheel for polishing according to. 23. The method for producing a polishing grindstone according to claim 22, wherein the reinforcing material is one or more selected from metal powder, organic fiber, inorganic fiber and metal fiber. 24. A polishing apparatus comprising the polishing tool according to any one of claims 11 to 15.