JP6674801B2 - Composite particles for abrasive grains and method for producing abrasives and composite particles for abrasive grains using the same - Google Patents

Description

  The present invention relates to composite particles mainly used as abrasive grains, an abrasive using the composite particles as abrasive grains, and a method for producing the composite particles.

Silicon carbide (SiC, new Mohs hardness: 13), boron carbide _(B 4 C, new Mohs hardness: 14), diamond (new Mohs hardness: 15) or the like materials, have a more than 13 high hardness in new Mohs hardness Therefore, it is used as a wire saw for cutting various ingots such as silicon and quartz and as a free abrasive for wafer wrap.

  In addition, the particle shape of these powders is generally a crushed shape as it is crushed, and has an indefinite shape having a sharp edge, and is effective for cutting and polishing with a strong cutting force due to the shape. It has been. As the polishing technique, blast processing in which a powder abrasive collides with an object to be processed, barrel polishing in which the object and the powder abrasive are put in a barrel and rotated, and the like are used.

  In recent years, visco-elastic polymer materials have been used to grind surfaces of complex shapes, deburr inner surfaces that cannot be reached by tools, perform R processing on edges, and process precision micro components. A technique such as viscoelastic flow processing in which a fluid (media) in which is dispersed is pressed and moved. Note that, here, a general method of processing by flowing abrasive grains, including a wet type and a dry type, is referred to as “flow processing”.

  In these fluid workings, abrasives and abrasive grains can be selected according to the purpose, but silicon carbide, boron carbide, high-hardness materials themselves such as diamond, the cutting power, the polishing power is too strong However, it cannot be used as abrasive grains for mirror-polishing, in which the surface of the object to be treated is polished into a mirror-like shape with a gloss.

  Therefore, materials such as alumina, zirconia, stainless steel, and glass, which are low in hardness (new Mohs hardness of 12 or less) and relatively spherical, are used as abrasive grains for mirror polishing. However, even if these materials are used, if the object to be processed is made of a soft material such as aluminum, copper, plastic or the like, it is necessary to further limit the use conditions.

  By the way, as examples in which silicon carbide powder is used as an abrasive for fluid working, Patent Document 1 and Patent Document 2 are known, for example. In Patent Document 1, an abrasive made of silicon carbide is used to roughen the surface of a SUS, titanium, aluminum, or molybdenum component.

  Patent Literature 2 discloses a blast treatment method capable of removing deposits without damaging the surface of the object. Here, the particle size of the abrasive grains made of silicon carbide or aluminum oxide is set to # 400 to # 800, and the pressure at which the abrasive contacts the surface of the workpiece is controlled.

  From these Patent Documents 1 and 2, the abrasive grains made of a material with high hardness such as silicon carbide are suitable for rough finishing or cutting the surface, but they do not damage the surface of the workpiece. It can be seen that when not giving, the use conditions need to be extremely limited.

  On the other hand, there has been proposed a method of using a combination of an abrasive and an elastic substance in order to adjust an excessive polishing force of the abrasive. For example, Patent Document 3 discloses an abrasive in which abrasive grains are attached to a surface of a nucleus containing water such as gelatin, but the abrasive loses moisture due to long-term storage or use. There is a concern that its performance will decrease. There is also a drawback that it cannot be used for fluid processing using water as a medium due to the solubility of the core.

  Further, for example, Patent Literature 4 discloses an abrasive capable of performing mirror polishing and glossy surface of a workpiece by blasting. This is to attach and fix abrasive grains to the surface of the core body having elasticity to form an abrasive, but in order to manufacture this abrasive, it is necessary to repeat the step of attaching and pressing the abrasive grains, Requires an abrasive sieving step. Therefore, there is a problem that the manufacturing process is complicated. In addition, this abrasive material suppresses the longevity and performance degradation by making the surface abrasive layer a masonry structure, but if the abrasive layer carried on the surface is consumed, it will be used as an abrasive. You still lose your ability.

  Further, for example, Patent Documents 5 and 6 disclose abrasive materials in which abrasive grains are dispersed in an elastic body such as rubber, acrylic resin, or urethane resin. These abrasives have the advantage that their production can be simplified as compared to abrasives that carry abrasive grains on the core surface, but these abrasives also perform better as the abrasives exposed on the surface wear. Since the deterioration occurs, there is a problem that the processing conditions change during repeated use. Further, in order to obtain desired elasticity due to the presence of abrasive grains in the elastic body, it is necessary to relatively increase the proportion of the elastic body. As a result, there is a problem in that the life of the abrasive is shortened because the number of abrasive grains exposed on the surface is reduced.

  As described above, some abrasives for performing mirror polishing by fluid working have been proposed so far, but there is a problem that their performance is still insufficient.

JP-A-11-28666 JP 2007-237389 A JP-A-2001-207160 International Publication No. WO2013 / 094492 No. 55-98565 JP-A-2015-20241

  Therefore, the present invention has been made to solve the drawbacks of the prior art, and an object of the present invention is to enable mirror polishing by flow processing, to be able to be used for a long time, and to further reduce the performance over time. An object of the present invention is to provide a composite particle having a small amount, an abrasive using the composite particle, and a method for producing the abrasive.

  The present invention relates to composite particles, and is characterized in that the particles are composed of a plurality of particles made of a material having a new Mohs hardness of 13 or more and a resin containing polyvinyl alcohol. The composite particles are preferably composed of particles of 95% by weight or less and resin of at least 5% by weight or more.

  The material having a new Mohs hardness of 13 or more is preferably silicon carbide, and the resin preferably contains an elastomer. This elastomer is a thermosetting elastomer, and the resin preferably contains a thermosetting resin.

  The present invention relates to an abrasive containing the composite particles as abrasive grains, and the composite particles preferably have an average particle diameter of 0.1 to 3.0 mmφ.

  Further, the present invention relates to a method for producing composite particles, wherein a first step of dispersing a powder composed of a material having a new Mohs hardness of 13 or more in an aqueous solution containing polyvinyl alcohol and an alkali metal salt of alginic acid, A second step of contacting the dispersion obtained in the first step with an aqueous solution containing a cation-containing compound, and a third step of drying the molded product obtained in the second step. It is a feature.

  When the composite particles of the present invention are used as abrasive grains of an abrasive, the cutting force and the polishing force of the particles exposed on the surface of the composite particles and the elasticity of the resin constituting the composite particles realize high hardness silicon carbide powder. It is possible to perform mirror polishing by flow processing that could not be performed.

  Further, when the composite particles of the present invention are in contact with the object to be treated as abrasive grains, the particles exposed on the surface are worn, and the resin containing polyvinyl alcohol is also gradually worn from the surface, so that the particles on the outermost surface Even if is consumed, new particles appear from below, so that the performance as an abrasive is less deteriorated and the life can be extended.

FIG. 2 is a schematic view of a composite particle of the present invention. FIG. 2 is a schematic diagram of an apparatus used in Example 1. FIG. 9 is a schematic diagram of an apparatus used in Example 3. FIG. 3 is a schematic view of a polishing test apparatus used in Examples and Comparative Examples.

  Hereinafter, an embodiment of the present invention will be described in detail, but the present invention is not limited thereto.

  The present invention is composed of a plurality of particles made of a material having a new Mohs hardness of 13 or more and a resin containing polyvinyl alcohol (PVA), and the plurality of particles are made of a material having a new Mohs hardness of 13 or more. .

  As described above, when a material having a new Mohs hardness of 13 or more and a relatively high hardness is used, a necessary polishing force can be obtained when the material is combined with a resin containing PVA. On the other hand, when a material having a new Mohs hardness of 12 or less is used, the polishing power is reduced, so that sufficient polishing cannot be performed.

Materials having a new Mohs hardness of 13 or more include, for example, silicon carbide, boron carbide, diamond and the like. Among them, silicon carbide is inexpensive and preferable. Further, the particle shape is a crushed shape as crushed, and is preferably an irregular shape having a sharp edge. This is because such particles are easily available and the particles have an edge so that an appropriate polishing force can be obtained.
FIG. 1 schematically shows a composite particle of the present invention, which is composed of a resin containing PVA and particles made of a material having a new Mohs hardness of 13 or more .

  Further, the particle diameter of the particles constituting the present invention is preferably 0.01 to 10%, more preferably 0.1 to 1% of the particle diameter of the final composite particles. If the particle size of the particles is too large with respect to the final particle size of the composite particles, sufficient elasticity cannot be obtained, and the object to be treated may be damaged. Also, if it is too small, sufficient polishing power cannot be obtained.

  The ratio of the particles constituting the composite particles is not particularly limited, and can be changed according to the use and purpose. However, since a certain degree of elasticity is required, the proportion of the particles is preferably at most 95 wt%, more preferably at most 90 wt%.

  Further, the particles constituting the composite particles are necessary for exhibiting the polishing force, and are preferably contained in a proportion of at least 10 wt%, more preferably at least 20 wt%. In the present invention, even when the proportion of particles is reduced and the number of particles exposed on the surface is reduced, the polishing power is adjusted, but the life of the abrasive is not immediately shortened.

  The present invention is composed of a resin containing PVA. By including PVA in the resin, it is possible to obtain composite particles which are optimal for mirror polishing by fluid working and can be used repeatedly for a long period of time.

  Even in the prior art, by carrying abrasive grains on the surface of the elastic body, or by dispersing the abrasive grains in the elastic body, the polishing force of the abrasive is adjusted, and mirror polishing by flow processing is enabled. Abrasives also have the disadvantage that if abrasive particles on the surface are worn, their performance will be reduced and their life will not be sufficient.

  In contrast, the present invention solves this problem by including PVA in the resin. In other words, when the present invention is used as abrasive grains, the particles on the surface are worn and the resin containing PVA gradually wears off from the surface, so that the particles initially buried in the resin are re-used on the surface with repeated use. Since it appears, the life of the abrasive can be extended.

  Therefore, when the composite particles of the present invention are used as abrasive grains of an abrasive, the processing conditions are easy to determine because there is little performance deterioration due to repeated use. In addition, since not only the particles exposed on the surface but also the particles inside are used, there is an advantage that the service life is long and economical.

  The average degree of polymerization of PVA used in the present invention is preferably 300 or more, and particularly preferably 500 or more. The saponification degree is preferably at least 70 mol%, more preferably at least 90 mol%.

  Further, other components can be added to modify the resin constituting the present invention. For example, an elastomer can be added to adjust the elasticity or the like. Among them, thermosetting elastomers are preferable, and examples thereof include natural rubber, acrylonitrile / butadiene copolymer, acrylate / butadiene copolymer, styrene / butadiene copolymer, and acryl / urethane copolymer.

  Further, phenol resin such as acrylic resin and thermosetting resin, melamine resin, epoxy resin, urethane resin, urea resin and the like can be added.

  These components can be selected to adjust the physical properties of the composite resin of the present invention in accordance with the material of the object to be treated and the like, but a plurality of components may be added.

  The resin constituting the present invention is preferably at least 5 wt% or more, more preferably 10 wt% or more. Further, the content is preferably at most 90 wt% or less, more preferably 80 wt% or less.

  Furthermore, it is preferable that 60% by weight or more of the entire resin constituting the composite resin is PVA, and more preferably 80% by weight or more. This is because if the content of PVA is too small, the resin is liable to be worn out too much, or it is difficult to be worn down depending on the added components, which leads to deterioration in performance as an abrasive and shortened life.

  The shape of the composite particles of the present invention is preferably a substantially spherical shape having no edges or the like as a whole, and is suitable for blast polishing or fluid working.

  The composite particles of the present invention can be used as abrasive grains, and an aggregate thereof can be used as an abrasive. This abrasive may include a medium such as water, oil, or a polymer material.

  At this time, the average particle size of the composite particles serving as the abrasive grains is preferably 0.1 to 3.0 mmφ, and more preferably 0.3 to 2.0 mmφ. The average particle size of the composite particles can be changed as necessary, but is preferably within the above-mentioned range because relatively uniform, substantially spherical particles can be easily produced.

  The composite particles of the present invention are obtained by a first step of dispersing a powder made of a material having a new Mohs hardness of 13 or more in an aqueous solution containing polyvinyl alcohol and an alkali metal salt of alginic acid, and this first step. It is manufactured through a step including a second step of bringing the dispersion into contact with an aqueous solution containing a cation-containing compound, and a third step of drying the molded product obtained in the second step.

  Here, sodium alginate is preferable as the alkali metal salt of alginic acid, and alkaline earth metal ions such as magnesium ion and calcium ion are preferable as the cation. As the cation-containing compound, calcium chloride is preferred.

In the first step of the production method of the present invention, first, an aqueous solution of a resin containing an alkali metal salt of alginic acid and PVA is prepared . The concentration of the resin containing PVA at this time may be freely determined according to the strength and elasticity of the target composite particles. However, a lower resin concentration is advantageous in terms of raw material cost and productivity. Further, the concentration of the alkali metal salt of alginic acid is preferably adjusted to be 0.5 to 2.0 wt% based on the mixed aqueous solution.

Next, a powder composed of a material having a new Mohs hardness of 13 or more is dispersed in the prepared mixed aqueous solution to prepare a raw material dispersion. At this time, the content ratio of the powder (abrasive grain ratio: the weight ratio of the powder to the resin component containing the alkali metal salt of alginic acid and PVA) can be freely determined according to the polishing force of the target composite particles. As the content ratio of the powder increases, the polishing power and the cutting power improve.

  Subsequently, in a second step, the raw material dispersion is brought into contact with an aqueous solution containing a cation-containing compound. At this time, the concentration of the cation-containing compound is preferably 0.5 to 2.0 mol / l. The particle size and shape of the composite particles can be controlled by the contact method at this time.

  In order to make the composite particles substantially spherical, the following method can be adopted. For example, by dropping the raw material dispersion from a tubular die, spraying from a spray die, or spraying from the outer periphery of a disk-shaped rotating body, a droplet of the raw material dispersion is generated, and this is used as a cation-containing compound. This is a method of contacting with an aqueous solution containing According to such a method, a substantially spherical composite particle can be produced. Further, the particle diameter of the composite particles can be changed by adjusting the diameter of the base, the spray pressure, the number of rotations of the rotating body, the amount of dropping, the viscosity of the solution, and the like.

  In the method of spraying the raw material dispersion from the outer periphery of the disk-shaped rotating body, it is possible to make the particle diameter smaller by increasing the number of rotations of the disk, but if the particle diameter is reduced to 0.3 mmφ or less, the shape becomes smaller. Are easily collapsed, and become more remarkable when the diameter is 0.1 mmφ or less.

  In addition, the method in which the raw material dispersion liquid is dropped from a tubular die is easy to produce a composite particle having a relatively large particle size. However, if the particle size is increased to 2.0 mmφ or more, the shape tends to be broken. In the case of 0 mmφ or less, it becomes more remarkable.

  Such deformation of the particle shape may cause damage to the object to be processed when used as abrasive grains. Further, the actually produced composite particles need to be passed through a sieve to make the particle size uniform, but the composite particles having a deformed shape cannot pass through the sieve, leading to a decrease in yield.

  The aqueous solution containing the cation-containing compound may be in a static state, but by stirring with a stirrer or the like, the reaction of the molded products is promoted, and furthermore, the adhesion of the molded products can be prevented. In addition, it is preferable to use a silicon tube and a roller pump for feeding the raw material dispersion liquid, whereby the amount of dripping can be made constant, and a molded article having a relatively uniform shape can be obtained.

  Finally, in the third step, the molded product obtained by contacting the raw material dispersion with an aqueous solution containing a cation-containing compound is thermally dried at 60 ° C. or more, shrunk, and heat-cured to obtain the composite particles of the present invention. Can be manufactured.

  The particle size distribution and particle size of the produced composite particles can be measured by a dry sieving test (JIS Z 8815-1994). Here, the sample is sieved using a plurality of different sieves having openings of 45 μm to 22.4 mm, and the mass of the sample remaining on each sieve is measured to determine the particle size distribution. In this specification, the cumulative distribution is described in a graph, and the particle size at a point where the cumulative value is 50% is defined as the average particle size.

Hereinafter, embodiments of the present invention will be described in detail.
<Example 1>
In Example 1, first, PVA (degree of polymerization: 1700, degree of saponification: 99 mol%) was added to water, stirred, and treated at 95 ° C. for 2 hours or more to obtain a PVA aqueous solution. In addition, sodium alginate was added to water and stirred until the mixture became transparent to obtain an aqueous sodium alginate solution.

Next, an aqueous sodium alginate solution was added to the aqueous PVA solution and stirred to prepare a mixed solution such that the concentration of PVA became 10.0 wt% and the concentration of sodium alginate became 2.0 wt%.

  In addition, GC # 3000 (average particle size: 4 μm) silicon carbide powder was added to the mixed aqueous solution and stirred to obtain a raw material dispersion. At this time, the ratio of silicon carbide was 85.0 wt% with respect to the total weight of silicon carbide, PVA, and sodium alginate.

  Next, as shown in FIG. 2, the obtained raw material dispersion liquid was sent at a flow rate of 3 ml / min using a roller pump equipped with a silicon tube having a tip of 0.8 mmφ attached thereto at 800 rpm. The solution was dropped on the center of the upper surface of the rotated disk-shaped rotating body of φ80 mm. The dropped raw material dispersion was sprayed from the outer periphery of the disk-shaped rotating body, and was brought into contact with a 1.0 mol / l aqueous solution of calcium chloride stirred with a stirrer.

  The raw material dispersion in contact with the aqueous calcium chloride solution precipitated as a substantially spherical molded product. This molded product was separated from the aqueous calcium chloride solution and washed with water. At this time, the mixture was passed through a sieve having a mesh size of 3 mm to remove a molded product that had a shape collapsed and had a shape in which the yarn was drawn in a drop shape.

  Subsequently, the obtained molded product was dried at 60 ° C. As a result, composite particles having an average particle size of 0.6 mm were obtained by thermosetting and shrinkage. By this operation, the composite particles finally obtained were 54 g, and the yield was 92%.

  A flow polishing test was performed using the aggregate of the produced composite particles as abrasive particles. Here, flow polishing in a liquid considered to be suitable for polishing a relatively soft material was performed.

  In the fluid polishing test, as shown in FIG. 4, first, an aluminum plate having a diameter of 5 cm was prepared as an object to be processed, and attached to the tip of a stainless steel rod having a diameter of 8 mm. Next, 200 ml of water and 100 ml of abrasive composite particles were placed in a 500 ml beaker, and an aluminum plate was rotated at 800 rpm for 1 hour in the beaker to polish the plate surface.

  The polishing performance was evaluated by measuring the surface roughness Ra and gloss before and after the treatment. Here, using SV-3100 manufactured by Mitutoyo Corporation, the arithmetic average surface roughness Ra was measured in accordance with the surface roughness standard of JIS B 0601: 1994. The specular gloss at a measurement angle of 60 ° was measured using MULTI GLOS 268 manufactured by Konica Minolta Co., Ltd. in accordance with the specular gloss of JIS Z 8741: 1997.

  As a result of the flow polishing test of Example 1, the surface roughness Ra before the treatment was about 0.20 μm, and the surface roughness Ra after the treatment was about 0.03 μm or less. Further, the glossiness measured by a gloss meter was about 200 before the treatment, but was about 500 after the treatment.

  Table 2 shows the results of a flow polishing test performed by repeatedly using an abrasive.

  From the above results, the composite particles of Example 1 can be used as abrasive grains that can be mirror-polished by fluid working, and the abrasive grains have less deterioration in performance even when used repeatedly, and have a long life. It can be seen that it is.

<Example 2>
In Example 2, composite particles were produced in the same manner as in Example 1, except that the rotation speed of the disk-shaped rotator was changed to 350 rpm. The average particle size of the composite particles was 1.6 mm, and the yield was 86%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 2 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that the abrasive grains have little deterioration in performance and have a long life even when used repeatedly. Was.

<Example 3>
In Example 3, as shown in FIG. 3, the same raw material dispersion as in Example 1 was dropped into a 1.0 mol / l aqueous solution of calcium chloride from a 0.8 mm diameter tubular die. The raw material dispersion in contact with the aqueous calcium chloride solution precipitated as a substantially spherical molded product. This molded product was separated from the aqueous calcium chloride solution and washed with water. At this time, the mixture was passed through a sieve having an opening of 5 mm to remove a molded product that had a shape that had collapsed and had a shape in which the yarn was drawn in a drop shape.

  Next, as a result of drying the obtained molded product at 60 ° C., composite particles having an average particle size of 2.5 mm were obtained, and the yield was 70%. In addition, when the prepared composite particles were visually observed, many particles having a deformed shape were observed as compared with Examples 1 and 2.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 3 can also be used as abrasive grains that can be mirror-polished by flow machining, and it is also found that the abrasive grains have little deterioration in performance and have a long life even when used repeatedly. Was.

<Example 4>
In Example 4, composite particles were produced in the same manner as in Example 3, except that a tubular die having a diameter of 1.2 mm was used. The average particle size of the composite particles was 3.5 mm, and the yield was 60%. In addition, when the produced composite particles were visually observed, many particles having a deformed shape were observed as compared with Examples 1, 2 and 3.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 4 can also be used as abrasive grains that can be mirror-polished by fluid processing, and this abrasive abrasive grain has little degradation in performance and has a long life even when used repeatedly. Was.

<Example 5>
In Example 5, composite particles were produced in the same manner as in Example 1, except that the number of revolutions of the disc-shaped rotator was changed to 1200 rpm. The average particle size of the composite particles was 0.3 mm, and the yield was 80%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 5 can also be used as abrasive grains that can be mirror-polished by flow processing, and this abrasive abrasive grain shows little deterioration in performance and long life even when used repeatedly. Was.

<Example 6>
In Example 6, composite particles were produced in the same manner as in Example 1, except that the rotation speed of the disk-shaped rotator was changed to 2000 rpm. The average particle size of the composite particles was 0.2 mm, and the yield was 75%. Further, when the prepared composite particles were observed using a magnifying glass, many of the particles having a deformed shape were observed as compared with Examples 1, 2 and 5.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 6 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that these abrasive grains have little deterioration in performance even when used repeatedly and have a long life. Was.

<Example 7>
In Example 7, composite particles were produced in the same manner as in Example 1, except that the rotation speed of the disk-shaped rotator was changed to 2500 rpm. The average particle size of the composite particles was 0.1 mm, and the yield was 65%. Further, when the prepared composite particles were observed using a magnifying glass, many particles having deformed shapes were observed as compared with Examples 1, 2, 5, and 6.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 7 can also be used as abrasive grains that can be mirror-polished by flow processing, and it is also found that the abrasive grains of this abrasive have little deterioration in performance even when used repeatedly and have a long life. Was.

<Example 8>
In Example 8, as shown in Table 1, composite particles were produced in the same manner as in Example 1, except that the ratio of silicon carbide, PVA, and alginic acid was changed. The average particle size of the composite particles was 0.7 mm, and the yield was 89%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 8 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that the abrasive grains have less deterioration in performance even when used repeatedly and have a long life. Was.

<Example 9>
In Example 9, as shown in Table 1, composite particles were produced in the same manner as in Example 1, except that the ratios of silicon carbide, PVA, and alginic acid were changed. The average particle size of the composite particles was 0.7 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 9 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that the abrasive grains have little deterioration in performance even when used repeatedly and have a long life. Was.

<Example 10>
In Example 10, an acrylonitrile-butadiene-based latex having a solid content of 40% was further added to a mixed aqueous solution of a PVA aqueous solution and a sodium alginate aqueous solution, and the ratio of silicon carbide, PVA, alginic acid and acrylonitrile-butadiene rubber was shown in Table 1. Except for the adjustment, composite particles were produced in the same manner as in Example 1. The average particle size of the composite particles was 0.7 mm, and the yield was 86%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 10 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that this abrasive grain has little deterioration in performance even when used repeatedly and has a long life. Was.

<Example 11>
In Example 11, a phenol resin solution was further added to a mixed aqueous solution of a PVA aqueous solution and a sodium alginate aqueous solution to adjust the ratio of silicon carbide, PVA, alginic acid, and phenol resin as shown in Table 1, except that the ratio was adjusted as shown in Table 1. In the same manner as in Example 1, composite particles were produced. The average particle size of the composite particles was 0.7 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 11 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that the abrasive grains have little deterioration in performance and have a long life even when used repeatedly. Was.

<Example 12>
In Example 12, an acrylonitrile / butadiene-based latex having a solid content of 40% and an acrylic resin solution were further added to a mixed aqueous solution of an aqueous PVA solution and an aqueous sodium alginate solution, and silicon carbide, PVA, alginic acid, an acrylic resin, and acrylonitrile / butadiene rubber were added. Except that the ratio of was adjusted as shown in Table 1, composite particles were produced in the same manner as in Example 1. The average particle size of the composite particles was 0.7 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 12 can also be used as abrasive grains that can be mirror-polished by flow processing, and this abrasive abrasive grain has little deterioration in performance and has a long life even when used repeatedly. Was.

<Example 13>
In Example 13, the composite was prepared in the same manner as in Example 1 except that a boron carbide powder of GC # 3000 (average particle size of 4 μm) was added instead of the silicon carbide powder of GC # 3000 (average particle size of 4 μm). Particles were made. The average particle size of the composite particles was 0.7 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 13 can also be used as abrasive grains that can be mirror-polished by fluid working, and it is also found that these abrasive grains have little deterioration in performance even when used repeatedly and have a long life. Was.

<Example 14>
In Example 14, the composite particles were produced in the same manner as in Example 1 except that diamond powder of GC # 3000 (average particle size of 4 μm) was added instead of silicon carbide powder of GC # 3000 (average particle size of 4 μm). Was prepared. The average particle size of the composite particles was 0.7 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  The composite particles of Example 14 can also be used as abrasive grains that can be mirror-polished by fluid processing, and this abrasive abrasive grain has little performance degradation even when used repeatedly and has a long life. Was.

Hereinafter, a comparative example will be described.
<Comparative Example 1>
In Comparative Example 1, the composite particles were produced in the same manner as in Example 1 except that alumina powder of GC # 3000 (average particle size of 4 μm) was added instead of silicon carbide powder of GC # 3000 (average particle size of 4 μm). Was prepared. The average particle size of the composite particles was 0.7 mm, and the yield was 80%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  It was found that the composite particles of Comparative Example 1 could not be mirror-polished by fluid working and could not be used as an abrasive for mirror-polishing.

<Comparative Example 2>
In Comparative Example 2, composite particles were produced in the same manner as in Example 1, except that a phenol resin was used instead of PVA. The average particle size of the composite particles was 0.6 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  With the composite particles of Comparative Example 2, mirror polishing by flow processing was possible, but the polishing performance was lower than when PVA was used, and it was also found that performance degradation due to repeated use was large.

<Comparative Example 3>
In Comparative Example 3, composite particles were produced in the same manner as in Example 1, except that a melamine resin was used instead of PVA. The average particle size of the composite particles was 0.6 mm, and the yield was 85%.

  Table 2 shows the results of a flow polishing test performed in the same manner as in Example 1 using the aggregate of the produced composite particles as abrasive grains.

  With the composite particles of Comparative Example 3, it was also possible to perform mirror polishing by flow processing, but it was also found that the polishing performance was lower than when PVA was used, and that the performance was significantly deteriorated by repeated use.

  The following Table 1 summarizes the composite particles of Examples 1 to 14 and Comparative Examples 1 to 3, and Table 2 summarizes the results of the flow polishing test. .

Claims (9)

Composite particles for abrasive grains , comprising a plurality of particles made of a material having a new Mohs hardness of 13 or more and a resin containing polyvinyl alcohol. The composite particles for abrasive grains according to claim 1, comprising 95 wt% or less of the particles and at least 5 wt% or more of the resin. The composite particles for abrasive grains according to claim 1, wherein the material having the new Mohs hardness of 13 or more is silicon carbide. The composite particles for abrasive grains according to any one of claims 1 to 3, wherein the resin contains an elastomer. The composite particles for abrasive grains according to claim 4, wherein the elastomer is a thermosetting elastomer. The composite particles for abrasive grains according to any one of claims 1 to 5, wherein the resin contains a thermosetting resin. An abrasive comprising the composite particles for abrasive grains according to any one of claims 1 to 6 as abrasive grains. The abrasive according to claim 7, wherein the abrasive composite particles have an average particle diameter of 0.1 to 3.0 mmφ. A first step of dispersing a powder made of a material having a new Mohs hardness of 13 or more in an aqueous solution containing polyvinyl alcohol and an alkali metal salt of alginic acid; and dispersing the dispersion obtained in the first step with a cation-containing compound. The abrasive step according to any one of claims 1 to 6, comprising: a second step of bringing the molded article obtained into contact with the aqueous solution containing the solution; and a third step of drying the molded product obtained in the second step. A method for producing composite particles.

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