JP2017171840A - Slurry for blast polishing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slurry for blast polishing capable of blast processing a target to be polished (work) with excellent smoothness.SOLUTION: There is provided a slurry for blast polishing containing a first particle having Mohs hardness of 8 or more and a dispersant and having particle diameter (Dv50%), where integrated particle volume from a large particle diameter side of particles measured after conducting an ultrasonic dispersion treatment at output of 40 W for 120 sec. is 50% of total particle volume, or 10 μm or less.SELECTED DRAWING: None

Description

  The present disclosure relates to a blast polishing slurry, and more particularly to a blast polishing slurry suitable for polishing an inorganic material such as a display substrate.

  In order to process substrates made of inorganic materials such as glass used for displays such as plasma displays and liquid crystal displays, more advanced technologies are required due to demands for larger displays, higher definition, and higher brightness. It has become to. As such a display substrate polishing method, a blast method, a barrel method, a lapping method, and the like are known.

  Of these, blasting methods such as drive blasting (sand blasting) and wet blasting are used to polish blast materials containing particles such as alumina, zirconia, glass beads, stainless steel, and silicon carbide from nozzles using a carrier gas such as compressed air. It is a technique for performing polishing by spraying on an object (workpiece).

  Patent Document 1 describes an invention relating to an abrasive characterized by comprising magnetic particles having a predetermined particle size distribution and a Mohs hardness (new Mohs hardness) of 1 to 12.

JP 2002-114968 A

  However, in the conventional blasting material as described above, there are cases where it is difficult to obtain a polishing object (workpiece) excellent in smoothness or cases where it is difficult to perform blasting with high processing efficiency. .

  Accordingly, an object of the present invention is to provide a blast polishing slurry capable of blasting an object to be polished (work) with excellent smoothness. Another object of the present invention is to provide a blast polishing slurry having excellent processing efficiency.

  The present inventor has intensively studied to solve the above problems. As a result, it has been found that the above problems can be solved by including particles (abrasive grains) having a specific hardness and a dispersion medium, and making the particle size distribution of the contained particles within a specific range, and the present invention is completed. It came to.

  That is, the above-mentioned objects include a first particle having a Mohs hardness of 8 or more and a dispersion medium, and a large particle diameter of the particle measured after an ultrasonic dispersion treatment at an output of 40 W for 120 seconds. The cumulative particle volume from the side can be achieved by a blast polishing slurry having a particle diameter (Dv 50%) corresponding to 50% of the total particle volume of 10 μm or less.

  According to the blast polishing slurry of the present invention, it is possible to provide a blast polishing slurry capable of smoothly blasting an object to be polished (workpiece). Further, according to the present invention, blasting can be performed with excellent processing efficiency.

It is the schematic of the apparatus used for the blasting method which concerns on one Embodiment of this indication.

  The present disclosure includes a first particle having a Mohs hardness of 8 or more and a dispersion medium, and is measured after performing ultrasonic dispersion treatment for 120 seconds at an output of 40 W, from the large particle diameter side of the particle. The particle diameter corresponding to 50% of the total particle volume (hereinafter referred to as “the particle diameter corresponding to 50% of the total particle volume from the large particle diameter side”) is simply “Dv50%”. Also referred to as a blast polishing slurry. According to such a blast polishing slurry, the object to be polished (work) can be smoothly blasted. Moreover, according to the blast polishing slurry, it is possible to blast the object to be polished (work) with an excellent processing efficiency.

  The blast polishing slurry is used in a different manner from the particles used in the barrel method and the lapping method in that it is sprayed onto the object to be polished, and is therefore required for the particles used in these different polishing methods. The physical properties are not necessarily common. For example, the particles used for the barrel method and the wrapping method and the particles used for the blasting method do not necessarily have a suitable particle diameter. Furthermore, the blasting method is roughly classified into a drive blast method and a wet blast method. In the wet blast method, particles are transported to the object to be polished by a dispersion medium (water, etc.), so finer particle size particles can be used compared to the drive blast method, and particles with a wide particle size can be used. There is the feature that it is. Therefore, in this way, in the wet blasting method, although particles having a wide range of particle sizes can be used, there is a demand for a technique that can further improve smoothness while maintaining good processing efficiency.

  Further, in the wet blasting method, there is a problem of clogging of the blast polishing slurry inside an apparatus used for blasting (especially, a flow path of the blast polishing slurry such as pipes and nozzles). Therefore, a technique that can effectively suppress the occurrence of such clogging is also demanded.

  On the other hand, the present inventor has intensively studied from the viewpoint of particle hardness and particle size distribution, and has completed the present invention. Although the detailed mechanism by which the above effect is obtained by the blast polishing slurry is unknown, it is presumed as follows.

  The particles (abrasive grains) contained in the blast polishing slurry are also required to have a certain degree of hardness as an abrasive. For this reason, when the slurry for blast polishing contains the first particles having a Mohs hardness of 8 or more, the object to be polished (work) can be blasted (polished) with an appropriate processing efficiency. Furthermore, when the particles contained in the blast polishing slurry are too large, it becomes difficult to achieve the desired smoothness. In particular, it is considered that when a blast polishing slurry containing excessively large particles is used, the smoothness of the polished object after polishing is significantly reduced. On the other hand, the slurry for blast polishing according to the present disclosure has a Dv50% of 10 μm or less measured after performing an ultrasonic dispersion treatment at an output of 40 W for 120 seconds, and has a Mohs hardness of 8 or more as the first particles. By containing the particles, the particle diameter and hardness of the particles are appropriately balanced for blasting. As a result, the polishing object can be smoothly blasted while obtaining practical processing efficiency.

  In addition, by containing the particles, the blast polishing slurry according to the present disclosure is effectively suppressed from clogging inside the blast processing apparatus (particularly, the flow path of the blast polishing slurry such as pipes and nozzles).

  Furthermore, in a processing method called blast processing, improvement in processing efficiency and improvement in smoothness are in a trade-off relationship with each other. Therefore, it can be said that in the technology relating to blasting, there is a demand for means capable of improving the smoothness while improving the processing efficiency. On the other hand, the slurry for blast polishing according to the present disclosure has a Dv50% of 10 μm or less measured after ultrasonic dispersion treatment at an output of 40 W for 120 seconds, and has a Mohs hardness of 8 as the first particles. By including the above particles, it is presumed that compatibility between processing efficiency and smoothness is achieved. In addition, the said mechanism is based on estimation and this invention is not limited to the said mechanism at all.

  Embodiments of the present invention will be described below. In addition, this invention is not limited only to the following embodiment.

  The slurry for blast polishing according to the present disclosure essentially includes particles (abrasive grains) and a dispersion medium. That is, the blast polishing slurry according to the present disclosure is a blast material for wet blasting.

<Particle>
When the particles contained in the blast polishing slurry of the present disclosure are measured after the blast polishing slurry is subjected to ultrasonic dispersion treatment for 120 seconds at an output of 40 W, the accumulated particle volume from the large particle diameter side is all The particle diameter (Dv 50%) corresponding to 50% of the particle volume is 10 μm or less. When Dv50% exceeds 10 μm, it becomes difficult to obtain excellent smoothness after blasting (processing).

  From the viewpoint of an even better balance between processing efficiency and smoothness, the upper limit of Dv50% of the particles contained in the blast polishing slurry is preferably 9.5 μm or less, more preferably 4.5 μm or less, and even more preferably It is 4.1 μm or less, particularly preferably 3.0 μm or less, and most preferably less than 3.0 μm.

  On the other hand, the lower limit of Dv50% of the particles is not particularly limited, but is preferably 1.0 μm or more from the viewpoint of the balance between processing efficiency and smoothness. The lower limit of Dv50% of the particles is preferably 1.2 μm or more, more preferably 1.5 μm or more, and further preferably more than 1.5 μm, from the viewpoint of the balance between processing efficiency and smoothness. Particularly preferably, it is 1.6 μm or more.

  In a preferred embodiment, Dv50% is 1.2 μm or more and 4.5 μm or less, more preferably 1.5 μm or more and 4.1 μm or less, and further preferably more than 1.5 μm and 4.1 μm or less. Particularly preferably, it is 1.6 μm or more and 3.0 μm or less, and most preferably 1.6 μm or more and less than 3.0 μm. If it is the said particle size distribution, the further favorable balance of processing efficiency and smoothness can be achieved more effectively. Moreover, if it is the said particle size distribution, it will become easy to suppress clogging of a processing apparatus (especially flow path of blast polishing slurries, such as piping and a nozzle).

  The present inventor found that the particle size distribution of the particles contained in the blast polishing slurry is an important factor for improving the processing efficiency and smoothness, and that the large content of particles is small in terms of improving the processing efficiency and smoothness. I found it preferable. That is, when the particles contained in the blast polishing slurry are too large, it becomes difficult to achieve the desired smoothness. In particular, when a blast polishing slurry in which coarse particles are excessively contained is used, the processing efficiency and smoothness of the polished object after polishing tend to decrease. On the other hand, when the particles contained in the blast polishing slurry are too small, the processing efficiency tends to decrease.

  In consideration of an even better balance between processing efficiency and smoothness, the cumulative particle volume from the large particle diameter side of the particles contained in the blast polishing slurry is equivalent to 3% of the total particle volume (Dv 3% ) Is preferably 2.0 μm or more. In the present specification, “particles measured after an ultrasonic dispersion treatment at an output of 40 W for 120 seconds and whose cumulative particle volume from the large particle diameter side corresponds to 3% of the total particle volume” “Diameter (Dv 3%)” is also simply referred to as “Dv 3%”. From the viewpoint of an even better balance between processing efficiency and smoothness, the lower limit of Dv 3% of the particles contained in the blast polishing slurry is more preferably 3 μm or more, further preferably more than 3 μm, particularly preferably 3 .5 μm or more. Further, the upper limit of Dv 3% is not particularly limited, but from the viewpoint of a better balance between processing efficiency and smoothness, the upper limit of Dv 3% of particles contained in the blast polishing slurry is preferably 20 μm or less, More preferably, it is 12 micrometers or less, More preferably, it is 7.0 micrometers or less, More preferably, it is 6.2 micrometers or less, Especially preferably, it is 5.0 micrometers or less, Most preferably, it is 4.0 micrometers or less.

  In a preferred embodiment, Dv 3% is preferably 2.5 μm or more and 7.0 μm or less, more preferably 3 μm or more and 6.2 μm or less, further preferably more than 3 μm and 5.0 μm or less, and particularly preferably. Is 3.5 μm or more and 4.0 μm or less. If it is the said particle size distribution, the further favorable balance of processing efficiency and smoothness can be achieved more effectively.

  Further, in consideration of an even better balance between processing efficiency and smoothness, a particle diameter corresponding to 0.1% of the total particle volume of the cumulative particle volume from the large particle diameter side of the particles contained in the blast polishing slurry ( Dv 0.1%) is preferably 15 μm or less. In this specification, “the cumulative particle volume from the large particle diameter side of the particle measured after performing the ultrasonic dispersion treatment at an output of 40 W for 120 seconds corresponds to 0.1% of the total particle volume. The “particle diameter” is also simply referred to as “Dv 0.1%”. Thereby, mixing of coarse particles is further suppressed. From the viewpoint of an even better balance between processing efficiency and smoothness, the upper limit of Dv 0.1% of the particles contained in the blast polishing slurry is preferably 15 μm or less, more preferably 12 μm or less, even more preferably. Is 10 μm or less, particularly preferably 7.0 μm or less, and most preferably less than 7.0 μm. The lower limit of Dv 0.1% is not particularly limited, but is, for example, 2.5 μm or more, preferably 3.0 μm or more, more preferably 4.0 μm or more, and further preferably 5.0 μm or more.

  In a preferred embodiment, Dv 0.1% is preferably 2.5 μm or more and 15 μm or less, more preferably 3.0 μm or more and 12 μm or less, and even more preferably 4.0 μm or more and 10 μm or less, particularly preferably. Is 5.0 μm or more and 7.0 μm or less, and most preferably 5.0 μm or more and less than 7.0 μm.

  The particles having a predetermined particle diameter as described above are pulverized while measuring the particle diameter of the particles by any pulverizing means such as a ball mill, roll mill, jet mill, etc., or classified (for example, water sieve classification). It can be prepared by any means such as.

  In this specification, the particle diameters of Dv 0.1%, Dv 3%, Dv 50%, etc. are subjected to an ultrasonic dispersion treatment at an output of 40 W for 120 seconds, and then a laser diffraction scattering type particle diameter particle size distribution analyzer is used. The value (equivalent diameter) obtained from the result of measuring the particle size distribution (volume basis) of the particles (particles in the slurry). In addition, more detailed measurement methods and conditions are as described in the examples.

  The blast polishing slurry of the present disclosure essentially contains first particles (first abrasive grains) having a Mohs hardness of 8 or more. In the present specification, “Mohs hardness” is also simply referred to as “hardness”, and “first particles having a Mohs hardness of 8 or more” are also simply referred to as “first particles” or “first abrasive grains”.

  In a blast polishing slurry that contains only relatively soft particles that do not include particles with a Mohs hardness of 8 or more, it is difficult to achieve high processing efficiency. The particles contained in the blast polishing slurry as the first particles may have a Mohs hardness of 8 (Vickers hardness of 1648 HV) or higher (upper limit = 10), but preferably have a Mohs hardness of 9 or higher (upper limit = 10). The “Mohs hardness” in this specification is a method for evaluating the hardness compared to the following 10 types of minerals as standard materials. The standard materials and samples are rubbed and scratched. However, it is determined that the hardness is low. When it is difficult to directly measure the Mohs hardness, the composition can be obtained from composition analysis, and can be judged from the Mohs hardness of substances having the same composition.

  In one embodiment, the blasting slurry includes first particles as a major component of the particles. The above-mentioned “including as the main component of the particles” means including 50% by mass or more of all particles included in the blast polishing slurry. The lower limit of the content of the first particles contained in the blast polishing slurry is preferably more than 50% by mass and more preferably 55% by mass or more with respect to the total mass of the contained particles. The upper limit of the content of the first particles contained in the blast polishing slurry is, for example, 100% by mass or less with respect to the total mass of the contained particles. In a preferred embodiment, the blast polishing slurry comprises the first particles in a proportion of preferably greater than 50 wt% and no greater than 100 wt%, more preferably 55 wt%, relative to the total weight of the contained particles. It is contained at a ratio of 100% by mass or less.

  When two or more types of particles having a Mohs hardness of 8 or more are included in the blast polishing slurry, in this specification, the particles having the highest Mohs hardness are treated as the first particles. That is, the first particle is a particle having a Mohs hardness of 8 or more and a maximum hardness among the particles constituting the blast polishing slurry. Further, when the blast polishing slurry includes particles of two or more kinds of materials having the same Mohs hardness of 8 or more (one digit after the decimal point), any of these particles is handled as the first particle. When two or more types of first particles having the same Mohs hardness are included in the blast material, the content of the first particles described above refers to the total amount of these two or more types of first particles.

The first particles may be formed of any material as long as the Mohs hardness is 8 or more. For example, as the first particles, osmium (Os, hardness = 8), yellow jade (Topaz, silicate / gemstone tovers containing fluorine and hardness, hardness = 8), tungsten carbide (tungsten carbide, WC) (hardness = 8) ), Zirconium boride (ZrB ₂ , hardness = 8), aluminum nitride (AlN, hardness = 8), corundum (Corundum, aluminum oxide, ruby, sapphire, steel ball, hardness = 9), titanium nitride (TiN, hardness = 9) ), Titanium carbide (TiC, hardness = 9), tantalum carbide (TaC, hardness = 9), zirconium carbide (ZrC, hardness = 9), chromium (hardness = 9), aluminum oxide (alumina, Al ₂ O ₃ , hardness = 9), silicon carbide (SiC, hardness = 9), aluminum boride (AlB, hardness = 9), boron carbide (B Examples thereof include particles such as ₄ C, hardness = 9), titanium boride (TiB ₂ , hardness = 9.5), beryllia (BeO, hardness = 9), diamond (hardness = 10), and the like. If the said hardness is the same, you may use individually by 1 type, or may be used with the form of a 2 or more types of mixture. From the viewpoint of availability, processing efficiency, and the like, the first particles are preferably silicon carbide and / or aluminum oxide particles (alumina particles). Furthermore, from the above viewpoint, the first particles preferably include aluminum oxide particles (alumina particles), and are preferably aluminum oxide particles (alumina particles).

  In a preferred embodiment, the blasting slurry further comprises second particles having a Mohs hardness less than the first particles. In the present specification, particles having a smaller Mohs hardness than the first particles are also simply referred to as “second particles” or “second abrasive grains”.

  Due to the presence of the second particles having a small Mohs hardness, excessive polishing by the first particles is suppressed, so that the smoothness of the polished object (work) after polishing can be further improved. .

  The second particle only needs to have a smaller Mohs hardness than the first particle, and is determined by the relative relationship between the Mohs hardness of each particle. Therefore, when two or more kinds of particles having a Mohs hardness of 8 or more are used, the particles having the highest Mohs hardness are the first particles, and the particles other than the first particles are handled as the second particles.

  The hardness of the second particles is not particularly limited as long as it is lower than that of the first particles. However, in consideration of an even better balance between processing efficiency and smoothness, the hardness of the first particles and the hardness of the second particles The difference is preferably 0.5 or more, more preferably 1 or more, and particularly preferably more than 1. Further, the difference between the hardness of the first particles and the hardness of the second particles is preferably 3 or less, more preferably 2 or less, and particularly preferably less than 2. In a preferred embodiment, the difference between the hardness of the first particles and the hardness of the second particles is preferably 0.5 or more and 3 or less, more preferably 1 or more and 2 or less, and particularly preferably more than 1. Is less than 2.

  Alternatively, the hardness of the second particles is preferably 5 or more and 8 or less, more preferably 6 or more and less than 8, and particularly preferably 6 or more and 7.5 or less. With such a hardness difference or hardness, an even better balance between processing efficiency and smoothness can be achieved more effectively.

  In this specification, when the second particles are a mixture of particles having different hardnesses, the hardness of the second particles is the sum of the hardness of each particle multiplied by the content (mass ratio) of the particles. To do. For example, when the second particles are composed of particles having hardness 6, particles having hardness 7 and particles having hardness 8 of 1: 3: 6 (mass ratio), the hardness of the second particles is 7.5 (= 6 × 0.1 + 7 × 0.3 + 8 × 0.6).

The second particles may be formed of any material as long as the material has a lower hardness than the first particles. For example, as the second particles, in addition to the particles exemplified for the first particles (excluding diamond), beryl (Beryl, hardness = 7.8), zirconium silicate (zircon) (ZrSiO ₄ , hardness) = 7.5), tourmaline (Tourmaline, hardness = 7.3), zirconium oxide (zirconia, hardness = 7), silicon (silicon, hardness = 7), quartz (Quartz / silicon dioxide / quartz / quartz glass) , Hardness = 7), steel (hardness = 5-8.5), garnet (hardness = 6.5-7), chromium dioxide (hardness = 6-7), agate (hardness = 6-7), ruthenium ( Hardness = 6.5), pyrite steel (Pyrite, hardness = 6.3), iridium (hardness = 6.25), silicon oxide (silica, hardness = 7), magnesium oxide (magnesia, hardness = 6.5), Ferrite (hardness = 6), pyroxene / clinopyroxene (Augite, hardness = 6), hematite (Hemateite, hardness = 6), orthofeldspar (Orthoclass / potassium-aluminum-containing silicate, hardness = 6), glass (hardness) = 6), inorganic particles such as cerium oxide (ceria, hardness = 6), titanium oxide (titania, hardness = 5.5-6); synthesis such as phenol resin, melamine resin, urea resin, polycarbonate resin, polyester resin Examples thereof include, but are not limited to, polymer resins. The said particle | grains may be used individually by 1 type, or may be used with the form of a 2 or more types of mixture. From the viewpoint of the smoothness of the object to be polished (work) after polishing, the blast polishing slurry preferably contains zirconium silicate particles (zircon particles) as the second particles. From the above viewpoint, the second particles are more preferably zirconium silicate particles (zircon particles). In the present specification, “zircon particles” are zirconium silicate mineral particles, which are naturally produced as zircon sand. Therefore, zircon sand or the like may be used as a material containing zirconium silicate particles (zircon particles). The ideal chemical composition of zircon is represented by ZrSiO ₄ . Zircon may contain metals (for example, titanium, iron, etc.) other than zirconium silicate (ZrSiO ₄ ) as impurities. When the blast material according to the present invention is used for polishing an inorganic material such as a display substrate, it is preferable that the metal impurities are small from the viewpoint of reducing the influence on the polishing target substrate. From the above points, the metal impurity content in the zircon particles is preferably 10% by mass or less, more preferably 5% by mass or less, and more preferably 1% by mass or less, based on the total mass of the zircon particles. It is particularly preferred. Zircon particles having high purity can be easily obtained, and those having a metal impurity content of 0.5% by mass or less can also be used.

  In a preferred embodiment, the blast polishing slurry comprises, as the first particles, diamond particles, tungsten carbide particles, alumina particles, silicon carbide particles, boron carbide particles, zirconium carbide particles, tantalum carbide particles, titanium nitride particles and boride. One kind selected from the group consisting of aluminum particles and the second particles are selected from the group consisting of tungsten carbide particles, glass particles, zircon particles, ceria particles, zirconia particles, titania particles, magnesia particles and zircon particles. 1 type or more. In a more preferred embodiment, the combination of the first particles and the second particles is a combination selected from the group consisting of diamond particles and tungsten carbide particles, tungsten carbide particles and glass particles, and alumina particles and zircon particles. In a particularly preferred embodiment, the combination of the first particles and the second particles is a combination of alumina particles and zircon particles.

  In the blast polishing slurry of the present disclosure, the particles (abrasive grains) are preferably composed of only the first particles (first abrasive grains) and the second particles (second abrasive grains).

  In the present specification, as described above, among the plurality of types of particles that can be included in the blast polishing slurry, the particle having the highest Mohs hardness is defined as the first particle, and the particles other than the first particle are defined as the second particle. And Here, the mixing ratio of the first particles and the second particles is not particularly limited, but the content of the first particles is preferably larger than the content of the second particles. Thereby, the smoothness of the workpiece can be further improved while maintaining a high machining efficiency.

  The blast polishing slurry includes, as particles, first particles of more than 50% by mass and less than 100% by mass and second particles of more than 0% by mass and less than 50% by mass (provided that the first particles More preferably, the total amount of the particles and the second particles is the total mass (100 mass%) of the particles contained in the blast polishing slurry. More preferably, the slurry for blast polishing contains, as particles, first particles of 55% by mass to 70% by mass and second particles of 30% by mass to 45% by mass (provided that the first particles The total amount of the particles and the second particles is the total mass (100% by mass) of the particles contained in the blast polishing slurry.)

  The blast polishing slurry according to the present disclosure includes a dispersion medium described in detail below together with the particles. The lower limit of the content of the particles relative to the entire blast polishing slurry is not particularly limited, but is, for example, 5% by mass or more, and preferably 10% by mass or more from the viewpoint of processing efficiency. From the viewpoint of processing efficiency, the upper limit of the content of particles with respect to the entire blast polishing slurry is, for example, 70% by mass or less, and preferably 45% by mass or less. In one embodiment, the content of particles with respect to the entire blast polishing slurry is 5% by mass or more and 70% by mass or less, and preferably 10% by mass or more and 45% by mass or less.

<Dispersion medium>
The blast polishing slurry according to the present disclosure further includes a dispersion medium in addition to the above-described particles (first particles and second particles added as necessary). A blasting slurry containing a dispersion medium in addition to the particles is suitably used as a blasting material for wet blasting. Compared to drive blasting (sand blasting) using particle powder (dry powder), wet blasting is less susceptible to air resistance because particles are carried by the dispersion medium (liquid), and the work environment is less likely to deteriorate due to scattering. . Further, since the object to be polished (work) is cooled by the dispersion medium (liquid), damage to the object to be polished (work) due to frictional heat can be suppressed. Furthermore, a dispersion medium (liquid) film is formed on the surface of the object to be polished (work), and the ejected particles are also washed by the dispersion medium (liquid), so that the particles bite into the object to be polished (work). There is an advantage that there is little. Furthermore, since the chemical | medical agent (additive) added as needed can be dissolved in a dispersion medium, there also exists an advantage that the process by the said chemical | medical agent can also be performed simultaneously with a blasting process.

  As the dispersion medium, water is preferably used, but water-soluble organic solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol and other lower alcohols, acetone, etc. In addition to these ketones, a mixture of one or more of these with water may be used. The dispersion medium used for the blast polishing slurry is preferably water containing as little impurities as possible. Specifically, pure water or ultrapure water from which foreign ions are removed through a filter after removing impurity ions with an ion exchange resin. Or distilled water is preferred.

  The pH of the blast polishing slurry containing the dispersion medium is, for example, 3 or more and 10 or less, and preferably 4 or more and 9 or less. The pH may be adjusted by appropriately combining acids such as hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, nitric acid and citric acid, and bases such as sodium hydroxide, potassium hydroxide, ammonia and triethanolamine.

  A dispersion aid that facilitates dispersion of particles may be added to the dispersion medium. Examples of such a dispersion aid include polycarboxylic acids (for example, polyacrylic acids such as polyacrylic acid, polyacrylamide, and acrylamide / sodium acrylate copolymer and salts thereof), lignin sulfonic acid, and the like. The amount of the dispersion aid (anti-cake agent) added is, for example, 0.1 mass% or more and 1.0 mass% or less with respect to the entire blast polishing slurry.

  The slurry for blast polishing may further contain other components such as an etching agent, a surfactant, an oxidizing agent, an anticorrosive agent, a chelating agent, an antiseptic agent, and an antifungal agent, as necessary. The amount of each component added when the blast polishing slurry contains the above-mentioned other components is not particularly limited, and the same amount as the conventional one can be adopted.

  The method for producing the blast polishing slurry is not particularly limited, and can be obtained, for example, by stirring and mixing the particles and, if necessary, a dispersion medium, a dispersion aid, and other components.

  The temperature at the time of mixing each component is not particularly limited, and is, for example, 10 ° C. or higher and 40 ° C. or lower, and may be heated to increase the dissolution rate. Further, the mixing time is not particularly limited.

<Polishing object (work), blasting method>
The blast polishing slurry of the present disclosure includes glass substrates for displays, silicon wafers, crystal wafers, optical elements such as lenses and prisms, jewelry, sapphire substrates for blue laser LEDs, glass substrates for magnetic disks, magnetic heads, and the like. It can be used for blasting such as surface smoothing, peening, deburring, etching (rib formation), etc., as a polishing object (work). Preferably, the blast polishing slurry of the present disclosure is used for blasting a display glass substrate, particularly for smoothing the surface (for example, smoothing a cut surface). That is, in one embodiment of the present invention, a blasting slurry for glass processing is provided. Examples of the glass substrate include quartz glass, soda lime glass, non-alkali glass, and borosilicate glass. In particular, the blast polishing slurry of the present disclosure can be suitably used for a cut surface of a glass substrate.

  In addition, according to the blast polishing slurry of the present disclosure, it is possible to blast the object to be polished (work) with an appropriate balance between processing efficiency and smoothness.

  Here, the smoothness of the object to be polished after blasting by the blast polishing slurry of the present disclosure is not particularly limited and can be appropriately adjusted depending on the application. For example, in the polishing object after blasting, Ra measured based on the method described in JIS B0601: 2001 is reduced by 20 nm or more with respect to Ra of the polishing object before blasting (that is, ΔRa is − 20 nm or less), preferably 50 nm or more (ΔRa is −50 nm or less), more preferably 80 nm or more (ΔRa is −80 nm or less), and particularly preferably 90 nm or more (ΔRa is −90 nm or less). Since the degree of reduction of Ra after blasting with respect to Ra of the object to be polished before blasting is preferably as large as possible, the upper limit is not particularly limited. In the present specification, the above-mentioned “Ra (and ΔRa) of the polishing target after blasting” is a value measured by the method described in Examples.

  In one embodiment of the present disclosure, a blasting method using the blast polishing slurry is provided. Here, except for using the blast polishing slurry of the present disclosure, the blasting method can be appropriately modified and applied if a method similar to the conventional method is necessary. Hereinafter, the present embodiment will be described in more detail with reference to FIG. 1, but the technical scope of the present invention is not limited at all.

  FIG. 1 is a schematic diagram showing a specific example (blasting apparatus 100) of an apparatus that can be suitably used in the blasting method of the present disclosure. The blasting apparatus 100 includes a blasting chamber 2, a tank 5 that houses a blasting slurry 4, a blasting material transport unit 6 that transports the blasting slurry 4 from the tank 5 to the blasting chamber 2, and a blasting chamber from a compressor. 2 includes a compressed air supply unit 8 for supplying compressed air to the air. When the blast polishing slurry 4 is in the form of a slurry containing a dispersion medium, the blast polishing slurry 4 accommodated in the tank 5 is preferably stirred by an arbitrary stirring means (not shown). By providing the stirring means, the particles in the slurry can be uniformly distributed. The tank 5 may be provided with a compressed air supply unit (not shown) that supplies pressurized gas (for example, compressed air) from the compressor to the tank 5.

  The blasting chamber 2 accommodates a stage 3 on which the polishing object 1 is disposed and an injection nozzle 7 for injecting the blast polishing slurry 4 transported by the blast material transport unit 6 onto the polishing object 1. The injection nozzle 7 has an opening in which an injection port through which the blast material 4 is injected is formed. The injection nozzle 7 may be installed in such a manner that the injection port faces the polishing object 1 and can be arbitrarily moved in the arrow x direction in FIG. 1. The shape of the opening of the injection nozzle 7 is not particularly limited, and may be a circular shape, a wide shape (for example, a wide shape having a width equal to or larger than the width of the polishing object 1), and the like. The polishing object 1 is usually arranged at a distance of about 0.1 mm or more and 10 mm or less from the opening of the injection nozzle 7. The spray nozzle 7 accelerates the blast polishing slurry 4 transported from the blast material transport section 6 with the compressed air supplied from the compressed air supply section 8 and sprays it onto the object 1 to be polished. Thereby, the polishing object 1 is blasted. The blast material (blast polishing slurry 4) spraying pressure is not particularly limited, and is, for example, 0.1 MPa to 1 MPa, preferably 0.1 MPa to 0.7 MPa. The blast material injection amount can be controlled by adjusting the compressed air pressure.

  The blast polishing slurry of the present invention may be a one-component type or a multi-component type including a two-component type in which a part or all of the blast polishing slurry is mixed in an arbitrary mixing ratio. . Further, when a polishing apparatus having a plurality of blast polishing slurry supply paths is used, two or more blast polishing slurries adjusted in advance so that the blast polishing slurry is mixed on the polishing apparatus may be used. Good.

  The blast polishing slurry of the present invention may be in the form of a stock solution, or may be prepared by diluting the stock solution of the blast polishing slurry with water. When the blast polishing slurry is a two-pack type, the order of mixing and dilution is arbitrary. For example, when one slurry is diluted with water and then mixed, or when diluted with water simultaneously with mixing, Another example is a case where the mixed blast polishing slurry is diluted with water.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples. In the following examples, unless otherwise specified, operations and measurements were performed under conditions of room temperature (20 to 25 ° C.) / Relative humidity of 40 to 50% RH.

Examples 1 to 12 and Comparative Example 1
The particles (abrasive grains) shown in Table 2 below were prepared. In Table 2 below, details of each particle (particles 1 and 2) are as follows. In Table 2, the silicon carbide (silicon carbide) particles are referred to as “SiC”, the alumina particles as “Al ₂ O ₃ ”, and the zircon particles as “ZrSiO ₄ ”, respectively. In addition, since the zircon particles used in this example are substantially composed of zirconium silicate (ZrSiO ₄ ) (with a metal impurity content of 0.5% by mass or less), the hardness of the zircon particles is that of zirconium silicate. Hardness (7.5).

  Particles 1 were prepared so as to have the composition shown in Table 2, or particles 1 and particles 2 were mixed by a dry method to prepare slurry particles 1-13. The obtained slurry particles 1 to 13 (before being dispersed in the dispersion medium) were each suspended in water so as to have a concentration of 30% by mass to prepare suspensions 1 to 13. Further, sodium acrylate as a dispersion aid was added to the obtained suspensions 1 to 13 so as to have a concentration of 0.2% by mass and stirred to obtain blast polishing slurries 1 to 13. Here, the pH of the blast polishing slurries 1 to 13 was 7.5.

  The particle size distribution of the particles contained in the blast polishing slurry thus prepared was measured under the following conditions. Based on the obtained particle size distribution, the cumulative particle volume from the large particle diameter side is equivalent to 50% of the total particle volume (Dv 50%), and the cumulative particle volume from the large particle diameter side is 3% of the total particle volume. % Particle diameter (Dv 3%), and the particle diameter (Dv 0.1%) corresponding to 0.1% of the total particle volume from the large particle diameter side. The results are shown in Table 2 below.

(Particle size distribution measurement)
≪Pretreatment≫
First, 0.5 ml of each of the above blast polishing slurries 1 to 13 was weighed as a pretreatment, and 30 ml of sodium hexametaphosphate (0.2% by mass) was added thereto. Each obtained sample was subjected to ultrasonic treatment at an ultrasonic output of 40 W for 120 seconds to obtain a particle size distribution measurement sample.

≪Measurement≫
Each sample was subjected to ultrasonic treatment under the above conditions, and then the particle size distribution (equivalent diameter) was measured under the following measurement conditions within 3 minutes.

(Measurement condition)
Measuring device: Microtrac MT3000II (manufactured by Microtrack Bell Co., Ltd.)
TR transmittance: 0.80 to 0.90
Measurement time: 30 seconds Number of measurements: 2 Particle permeability: Transmission (TRANSPARENT)
Particle refractive index: 1.77
Particle shape: Non-spherical Solvent refractive index: 1.33
Calculation mode: MT3000II
Distribution display: Volumetric circulator condition Flow rate: 50%
Ultrasonic output: 40W
Ultrasonic time: 240 seconds.

  Using the blast polishing slurries 1 to 13 prepared as described above, the workpiece (front side) was blasted under the following conditions. The blast polishing slurry was stored in a closed tank equipped with a stirrer, and during blasting, the blast polishing slurry was blasted while being stirred with the stirrer.

(Blasting conditions)
Apparatus: Mipot MBM-2 (Mako Co., Ltd.)
Workpiece: non-alkali glass (30mm x 30mm, thickness 3mm)
Nozzle opening to workpiece distance: 0.5mm
Nozzle position: Fixed nozzle opening shape: Circular (diameter 1 mm)
Nozzle angle: perpendicular to the workpiece (90 °) (jetting with the nozzle position fixed)
Air pressure: 0.4 MPa.

  About the workpiece | work which blasted on the said conditions, the reduction | decrease mass (g) and surface roughness ((DELTA) Ra) of the workpiece | work mass after a process were evaluated. The processing time was 10 seconds in the following (reduction mass of workpiece mass after processing), and 1 second in the following (surface roughness). The results are shown in Table 2 below.

(Decreased mass of workpiece after machining: Machining efficiency)
The decrease mass (W (g)) of the workpiece mass after machining relative to the workpiece mass before machining was measured. In addition, that the reduction | decrease mass (W (g)) of the workpiece | work mass after a process is large means that it was grind | polished more (largely) and means that processing efficiency is high.

(Surface roughness)
“Ra” indicating the surface roughness on the machined surface was measured for the workpiece before and after machining, and a value obtained by subtracting Ra before machining from Ra after machining was defined as ΔRa. A lower value of ΔRa indicates that the processed surface is flattened. Ra was measured using a non-contact surface shape measuring instrument (laser microscope VK-X200, manufactured by Keyence Corporation) based on the method described in JIS B0601: 2001. As measurement conditions of the non-contact surface shape measuring machine, the measurement range (viewing angle) was 280 μm × 210 μm.

(Clogged)
Each of the blast polishing slurries 1 to 13 was evaluated for clogging. At this time, the clogging was evaluated by measuring the flow rate (recovered amount) of the slurry as follows. First, under the above blasting conditions, the blasting apparatus was operated for 1 minute with no workpiece installed, and the amount (weight) of the slurry recovered by the slurry recovery container was measured. The operation was set as one set, and 16 sets were performed. The average (A) of the first three sets of recovered slurry (weight) (A) and the average (B) of the last three sets of recovered slurry (weight) were compared to evaluate the ease of clogging of the slurry. In addition, when changing the blast polishing slurry, the inside of the processing apparatus was cleaned and replaced with water and then evaluated. The evaluation criteria are as follows.

(Evaluation criteria for clogging)
X: The reduction rate of the average (B) of the recovery amount relative to the average (A) of the recovery amount is 10% or more. ○: The reduction rate of the average (B) of the recovery amount relative to the average (A) of the recovery amount is 10. %Less than.

  From Table 2 above, according to the blast polishing slurry according to the example, it is possible to obtain an object to be polished (work) having high processing efficiency and excellent smoothness after processing. Further, according to the blast polishing slurry according to the embodiment, clogging of the processing apparatus (the flow path of the blast polishing slurry such as pipes and nozzles) can be suppressed.

1 polishing object,
4 Blasting slurry,
7 spray nozzle,
100 Blasting device.

Claims (7)

First particles having a Mohs hardness of 8 or more;
A dispersion medium,
The particle diameter (Dv 50%) corresponding to 50% of the total particle volume is 10 μm or less, as measured after the ultrasonic dispersion treatment at an output of 40 W for 120 seconds, A slurry for blast polishing.   The blast polishing slurry according to claim 1, further comprising second particles having a Mohs hardness smaller than that of the first particles.   The slurry for blast polishing according to claim 2, wherein the content of the first particles is larger than the content of the second particles.   The blast polishing slurry according to claim 2 or 3, wherein the second particles include zircon particles.   The slurry for blast polishing according to any one of claims 1 to 4, wherein a particle diameter (Dv 3%) corresponding to 3% of the total particle volume of an integrated particle volume from the large particle diameter side of the particle is 3 µm or more. .   The slurry for blast polishing according to any one of claims 1 to 5, wherein the first particles are alumina particles.   The slurry for blast polishing according to any one of claims 1 to 6, which is used for glass processing.