JP6730054B2 - Blast polishing slurry - Google Patents

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 technology is required along with the demand for larger displays, higher definition, and higher brightness. It has become to. As a polishing method for such a display substrate, a blast method, a barrel method, a lapping method and the like are known.

Among them, the blast method such as dry blast (sand blast) and wet blast is performed by polishing a blast material containing particles such as alumina, zirconia, glass beads, stainless steel, and silicon carbide from a nozzle by using a carrier gas such as compressed air. This is a technique for spraying and polishing an object (work).

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

Japanese Patent Laid-Open No. 2002-114968

However, with the conventional blast materials as described above, there are cases where it is difficult to obtain an object to be polished (workpiece) having excellent smoothness, or it is difficult to perform blast processing with high processing efficiency. ..

Therefore, it is an object of the present invention 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 conducted diligent research in order to solve the above problems. As a result, it has been found that the above problems can be solved by containing particles (abrasive particles) having a specific hardness and a dispersion medium and setting the particle size distribution of the particles contained within a specific range, and completes the present invention. Came to.

That is, the above-mentioned various objects include the first particles having a Mohs hardness of 8 or more, and a dispersion medium, and are measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W and have a large particle diameter. This can be achieved by a blast polishing slurry having a particle diameter (Dv50%) corresponding to 50% of the total particle volume from the side, 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 a schematic diagram of an apparatus used for a blasting method concerning one embodiment of this indication.

The present disclosure includes first particles having a Mohs hardness of 8 or more and a dispersion medium, and is measured after performing an ultrasonic dispersion treatment at an output of 40 W for 120 seconds. The particle diameter corresponding to 50% of the total particle volume of the integrated particles (hereinafter, "the particle diameter corresponding to 50% of the total particle volume of the integrated particle volume from the large particle diameter side" is simply referred to as "Dv50%"). ) Is 10 μm or less. With such a blast polishing slurry, an object to be polished (workpiece) can be smoothly blasted. Further, according to the blast polishing slurry, the object to be polished (work) can be blast processed with excellent processing efficiency.

The blast polishing slurry has a different usage form from the particles used in the barrel method and the lapping method in that it is used by being sprayed on the object to be polished, and therefore, the particles used in these different polishing methods are required. The physical properties are not always the same. For example, the particles used in the barrel method or the lapping method and the particles used in the blasting method do not necessarily have the same preferable particle diameter. Further, the blasting method is roughly classified into a drive blast method and a wet blast method. In the wet blast method, particles are carried to the object to be polished by the dispersion medium (water etc.), so it is possible to use particles with a finer particle size compared to the dry blast method, and it is possible to use particles with a wide range of particle sizes. It is characterized by Therefore, as described above, in the wet blasting method, although particles having a wide range of particle diameters can be used, there is a demand for a technique capable of further improving smoothness while maintaining good processing efficiency.

Furthermore, in the wet blasting method, there is a problem that clogging of the blasting slurry inside the device used for the blasting (particularly the flow path of the blasting slurry such as piping and nozzles) occurs. Therefore, there is also a demand for a technique capable of effectively suppressing the occurrence of such clogging.

On the other hand, the present inventor has conducted extensive studies from the viewpoint of particle hardness and particle size distribution, and has completed the present invention. The detailed mechanism by which the above effects are obtained by the blast polishing slurry is unknown, but it is presumed as follows.

The particles (abrasive particles) contained in the blast polishing slurry are also required to have a certain degree of hardness as an abrasive. Therefore, by including the first particles having a Mohs hardness of 8 or more in the blast polishing slurry, it is possible to blast process (polish) an object to be polished (workpiece) with appropriate processing efficiency. Furthermore, if 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 the smoothness of the object to be polished after polishing is remarkably deteriorated when the slurry for blast polishing containing excessively large particles is used. In contrast, the blast polishing slurry 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 including the particles of No. 3, the particle size and hardness of the particles are appropriately balanced for blasting, and as a result, the object to be polished can be smoothly blasted while obtaining practical processing efficiency.

Further, by containing the above particles, the blast polishing slurry according to the present disclosure effectively suppresses clogging inside the blast processing apparatus (particularly, the flow path of the blast polishing slurry such as the pipe and the nozzle).

Further, in the processing method called blast processing, the improvement in processing efficiency and the improvement in smoothness are in a trade-off relationship with each other. Therefore, it can be said that the technique relating to blasting requires a means capable of improving the smoothness as well as improving the working efficiency. In contrast, the blast polishing slurry according to the present disclosure has a Dv50% of 10 μm or less measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W, and has a Mohs hardness of 8 as the first particles. It is presumed that the inclusion of the above particles achieves compatibility between processing efficiency and smoothness. The above mechanism is speculative, and the present invention is not limited to the above mechanism.

Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments.

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

<Particles>
The particles contained in the blast polishing slurry of the present disclosure have a total cumulative particle volume from the large particle size side when the blast polishing slurry is subjected to ultrasonic dispersion treatment for 120 seconds at an output of 40 W and then measured. The particle diameter (Dv50%) 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 a further good 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, still more 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 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. With this particle size distribution, a better balance between processing efficiency and smoothness can be achieved more effectively. Further, with the above particle size distribution, it becomes easier to suppress clogging of the processing device (particularly the flow path of the blast polishing slurry such as the pipes and nozzles).

The present inventor has 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 the smoothness, and that the content of large particles is small in terms of improving the processing efficiency and the smoothness. I found it preferable. That is, if 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 containing excessively large particles is used, the processing efficiency and smoothness of the object to be polished after polishing tend to be lowered. On the other hand, if the particles contained in the blast polishing slurry are too small, the processing efficiency tends to decrease.

Further, in consideration of a further good balance between processing efficiency and smoothness, the cumulative particle volume of the particles contained in the slurry for blast polishing from the large particle diameter side corresponds to 3% of the total particle volume (Dv3%). ) Is preferably 2.0 μm or more. In addition, in the present specification, “a particle having an integrated particle volume measured from the large particle diameter side of the particle measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W corresponds to 3% of the total particle volume. The “diameter (Dv3%)” is also simply referred to as “Dv3%”. From the viewpoint of a further good balance between processing efficiency and smoothness, the lower limit of Dv3% of the particles contained in the slurry for blast polishing is more preferably 3 μm or more, further preferably more than 3 μm, and particularly preferably 3 It is at least 5 μm. Further, the upper limit of Dv3% is not particularly limited, but from the viewpoint of a further good balance between processing efficiency and smoothness, the upper limit of Dv3% of the particles contained in the blast polishing slurry is preferably 20 μm or less, It is more preferably 12 μm or less, still more preferably 7.0 μm or less, even more preferably 6.2 μm or less, particularly preferably 5.0 μm or less, and most preferably 4.0 μm or less.

In a preferred embodiment, Dv3% 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. With this particle size distribution, a better balance between processing efficiency and smoothness can be achieved more effectively.

In consideration of a better balance between processing efficiency and smoothness, the particle size of the particles contained in the blast polishing slurry from the large particle size side corresponds to 0.1% of the total particle volume (particle size). Dv 0.1%) is preferably 15 μm or less. In the present specification, “the cumulative particle volume from the large particle diameter side of the particles, which is measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W, corresponds to 0.1% of the total particle volume. The particle size" is also simply referred to as "Dv 0.1%". This further suppresses the inclusion of coarse particles. From the viewpoint of a 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, and further 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, even more preferably 4.0 μm or more and 10 μm or less, and 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 crushed while measuring the particle diameter of the particles by an arbitrary crushing means such as a ball mill, a roll mill, a jet mill or the like, or the particles are classified (for example, water sieve classification). ) Or the like.

In the present specification, the particle diameters of Dv0.1%, Dv3%, Dv50%, etc. are ultrasonically dispersed for 120 seconds at an output of 40 W, and then a laser diffraction/scattering particle diameter particle size distribution measuring device is used. Is 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 measuring methods and conditions are as described in Examples.

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

With a blast polishing slurry containing only relatively soft particles such that particles having a Mohs hardness of 8 or more are not included, 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 more (upper limit=10), but preferably have a Mohs hardness of 9 or more (upper limit=10). The "Mohs hardness" in the present specification is a method of evaluating the hardness compared with the following 10 kinds of minerals as standard substances, and rubbing the standard substance with the sample and scratching the sample. 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 the composition analysis, and it can be judged from the Mohs hardness of a substance having the same composition.

In one embodiment, the blast polishing slurry comprises first particles as a major component of the particles. The above-mentioned "comprising as a main component of particles" means that it is contained in a proportion of 50% by mass or more of all particles contained in the slurry for blast polishing. 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, based on 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 based on the total mass of the contained particles. In one preferred embodiment, the blast polishing slurry contains the first particles in a proportion of preferably more than 50% by mass and 100% by mass or less, more preferably 55% by mass, based on the total mass of the contained particles. It is contained at a ratio of not less than 100% by mass.

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

The first particles may be formed of any material as long as the particles have a Mohs hardness of 8 or more. For example, the first particles include osmium (Os, hardness=8), yellow balls (Topaz, silicate containing aluminum and fluorine, gemstone Tobers, 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 ₄ C, hardness=9), titanium boride (TiB ₂ , hardness=9.5). Examples thereof include particles of beryllia (BeO, hardness=9), diamond (hardness=10), and the like. The particles may be used alone or in the form of a mixture of two or more as long as they have the same hardness. From the viewpoint of easy availability, processing efficiency, etc., it is preferable that the first particles are silicon carbide and/or aluminum oxide particles (alumina particles). From the above viewpoint, the first particles more preferably contain aluminum oxide particles (alumina particles), and are preferably aluminum oxide particles (alumina particles).

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

Since the presence of the second particles having a low Mohs hardness suppresses excessive polishing by the first particles, it is possible to further improve the smoothness of the polishing target (workpiece) after polishing. ..

The second particles need only have a smaller Mohs hardness than the first particles, and are determined by the relative relationship between the Mohs hardness of each particle. Therefore, when using two or more types of particles having a Mohs hardness of 8 or more, the particle having the highest Mohs hardness is the first particle, and particles other than the first particle are treated 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, but in consideration of a further good balance between processing efficiency and smoothness, the hardness of the first particles and the hardness of the second particles are The difference is preferably 0.5 or more, more preferably 1 or more, and particularly preferably more than 1. 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. It 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, a better balance between processing efficiency and smoothness can be more effectively achieved.

In the present specification, when the second particles are a mixture of particles having different hardness, the hardness of the second particles is the sum of the hardness of each particle multiplied by the content (mass ratio) of the particle. To do. For example, when the second particles are composed of particles having a hardness of 6, particles having a hardness of 7 and particles having a hardness of 8 in a mixing ratio 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 hardness lower than that of the first particles. For example, as the second particles, in addition to the particles (excluding diamond) exemplified in the first particle, 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 raw material) , Hardness = 7), steel steel (hardness = 5 to 8.5), garnet (hardness = 6.5 to 7), chromium dioxide (hardness = 6 to 7), agate (hardness = 6 to 7), ruthenium ( Hardness=6.5), Pyrite (Pyrite, Hardness=6.3), Iridium (Hardness=6.25), Silicon oxide (Silica, Hardness=7), Magnesium oxide (Magnesia, Hardness=6.5), Iron oxide (hardness=6), pyroxene/pyroxene (Augite, hardness=6), hematite (Hematite, hardness=6), orthoclase (Orthoclase/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 of the resin include polymer resins, but not limited to these. The particles may be used alone or in the form of a mixture of two or more kinds. From the viewpoint of 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, it is even more preferable that the second particles are zirconium silicate particles (zircon particles). In the present specification, the “zircon particles” are zirconium silicate mineral particles, which are naturally produced as zircon sand. Therefore, zircon sand or the like may be used as the material containing zirconium silicate particles (zircon particles). The ideal chemical composition of zircon is represented by ZrSiO ₄ . Zircon may contain a metal (for example, titanium, iron, etc.) other than zirconium silicate (ZrSiO ₄ ) as an impurity. 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 amount of metal impurities is small from the viewpoint of reducing the influence on the substrate to be polished. From the above points, the content of metal impurities in the zircon particles is preferably 10 mass% or less, more preferably 5 mass% or less, and more preferably 1 mass% or less, based on the total mass of the zircon particles. Is particularly preferable. Zircon particles having a 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 diamond particles, tungsten carbide particles, alumina particles, silicon carbide particles, boron carbide particles, zirconium carbide particles, tantalum carbide particles, titanium nitride particles and boride as the first particles. One selected from the group consisting of aluminum particles, and the second particle selected from the group consisting of tungsten carbide particles, glass particles, zircon particles, ceria particles, zirconia particles, titania particles, magnesia particles and zircon particles. And one 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 particles) are preferably composed of only the first particles (first abrasive particles) and the second particles (second abrasive particles).

In the present specification, as described above, among the plurality of types of particles that can be contained in the blast polishing slurry, the particle having the highest Mohs hardness is the first particle, and the particles other than the first particle are the second particles. 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 higher than the content of the second particles. This makes it possible to further improve the smoothness of the work while maintaining a high processing efficiency.

The blast polishing slurry contains, 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% by mass) of the particles contained in the blast polishing slurry. More preferably, the blast polishing slurry contains, as particles, 55% by mass or more and 70% by mass or less of first particles and 30% by mass or more and 45% by mass or less of second particles (provided that the first particles are 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 the above-mentioned particles and a dispersion medium described in detail below. The lower limit of the content of particles with respect to the entire slurry for blast polishing is not particularly limited, but from the viewpoint of processing efficiency, it is, for example, 5% by mass or more, and preferably 10% by mass or more. 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 slurry for blast polishing is 5% by mass or more and 70% by mass or less, 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 particles (the first particles and the second particles that are added as necessary). A blast polishing slurry containing a dispersion medium in addition to the above particles is suitably used as a blast material for wet blasting. Compared to dry-blasting (sandblasting), which uses particle powder (dry powder), wet-blasting is less susceptible to air resistance because particles are carried by a dispersion medium (liquid), and the work environment is less likely to deteriorate due to scattering. .. Further, since the object to be polished (workpiece) is cooled by the dispersion medium (liquid), damage to the object to be polished (workpiece) due to frictional heat is suppressed. Furthermore, a film of the dispersion medium (liquid) is formed on the surface of the polishing target (work), and the sprayed particles are also washed by the dispersion medium (liquid), so that the particles penetrate into the polishing target (work). There is an advantage that there are few. Furthermore, since a chemical agent (additive) that is added as needed can be dissolved in the dispersion medium, there is an advantage that the treatment with the chemical agent can be performed simultaneously with the blasting.

As the dispersion medium, water is preferably used, but an organic solvent soluble in water, for example, lower alcohol such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, or acetone. Other than 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 obtained by removing foreign matters 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 acid, polyacrylamide, polyacrylic acids such as acrylamide/sodium acrylate copolymer and salts thereof), and ligninsulfonic acid. The addition amount of the dispersion aid (anti-cake agent) is, for example, 0.1% by mass or more and 1.0% by mass or less based on the entire blast polishing slurry.

The blast polishing slurry 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, if necessary. When the blast polishing slurry contains the above-mentioned other components, the addition amount of each component is not particularly limited, and the same amount as the conventional amount can be adopted.

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

The temperature at the time of mixing the components 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. Also, the mixing time is not particularly limited.

<Polishing object (work), blasting method>
INDUSTRIAL APPLICABILITY The blast polishing slurry of the present disclosure can be used for not only glass substrates for displays but also 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, etc. It can be used for blasting such as surface smoothing, peening, deburring, etching (rib formation) of the surface of a workpiece as a polishing object (work). Preferably, the blast polishing slurry of the present disclosure is used for blasting a glass substrate for a display, particularly for surface smoothing (for example, smoothing a cut surface). That is, in one embodiment of the present invention, a blast polishing slurry for glass processing is provided. Examples of the glass substrate include quartz glass, soda-lime glass, alkali-free glass, borosilicate glass, and the like. In particular, the blast polishing slurry of the present disclosure can be suitably used for a cut surface of a glass substrate.

Further, according to the blast polishing slurry of the present disclosure, an object to be polished (workpiece) can be blast processed with an appropriate balance of processing efficiency and smoothness.

Here, the smoothness of the object to be polished after blast processing with 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 object to be polished after blasting, Ra measured based on the method described in JIS B0601:2001 decreases by 20 nm or more with respect to Ra of the object to be polished before blasting (that is, ΔRa is − It is preferably 20 nm or less, more preferably 50 nm or more (ΔRa is −50 nm or less), further preferably 80 nm or more (ΔRa is −80 nm or less), and particularly preferably 90 nm or more (ΔRa is −90 nm or less). The higher the degree of reduction of Ra after blasting with respect to Ra of the object to be polished before blasting, the better, so the upper limit is not particularly limited. In the present specification, the “Ra (further, ΔRa) of the object to be polished after blasting” is a value measured by the method described in the examples.

In one embodiment of the present disclosure, there is provided a blasting method using the above blast polishing slurry. Here, the blasting method can be appropriately modified and applied if the same method as the conventional one is required except that the blast polishing slurry of the present disclosure is used. 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 (blast processing apparatus 100) of an apparatus that can be preferably used in the blast processing method of the present disclosure. The blast processing apparatus 100 includes a blast processing chamber 2, a tank 5 containing a blast polishing slurry 4, a blast material transport unit 6 for transporting the blast polishing slurry 4 from the tank 5 to the blast processing chamber 2, and a compressor to the blast processing chamber. 2 is a compressed air supply unit 8 for supplying compressed air. When the blast-polishing slurry 4 is in the form of a slurry containing a dispersion medium, the blast-polishing slurry 4 contained in the tank 5 is preferably agitated by an arbitrary agitating means (not shown). By providing the stirring means, the particles in the slurry can be uniformly distributed. Further, the tank 5 may be provided with a compressed air supply unit (not shown) that supplies a pressurized gas (for example, compressed air) from the compressor to the tank 5.

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

The blast polishing slurry of the present invention may be a one-liquid type, or may be a multi-liquid type including a two-liquid type in which a part or all of the blast polishing slurry is mixed at 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 preliminarily adjusted so that the blast polishing slurries are mixed on the polishing apparatus are used. Good.

Further, 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-component type, the order of mixing and diluting is arbitrary, for example, when diluting one slurry with water and then mixing them, or when diluting with water at the same time as mixing, Moreover, the case where the mixed slurry for blast polishing is diluted with water etc. is mentioned.

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 to the following examples. In addition, in the following examples, unless otherwise specified, operations and measurements were performed at room temperature (20 to 25° C.)/relative humidity of 40 to 50% RH.

Examples 7 to 11, Reference Examples 1 to 6, 12 and Comparative Example 1
The particles (abrasive particles) shown in Table 2 below were prepared. In addition, in Table 2 below, details of each particle (particles 1 and 2) are as follows. In Table 2 below, silicon carbide (silicon carbide) particles are referred to as “SiC”, alumina particles are referred to as “Al ₂ O ₃ ”, and zircon particles are referred to as “ZrSiO ₄ ”. Further, since the zircon particles used in this example are substantially composed of zirconium silicate (ZrSiO ₄ ) (metal impurity content is 0.5 mass% or less), the hardness of the zircon particles is zirconium silicate. Hardness (7.5).

Particles 1 were prepared so that the compositions shown in Table 2 were obtained, or particles 1 and particles 2 were mixed by a dry method to prepare particles 1 to 13 for slurry. The obtained slurry particles 1 to 13 (before being dispersed in the dispersion medium) were suspended in water so as to have a concentration of 30% by mass, to prepare suspensions 1 to 13. Furthermore, sodium polyacrylate as a dispersion aid was added to each of the obtained suspensions 1 to 13 so as to have a concentration of 0.2% by mass, and the mixture was stirred to prepare blast polishing slurries 1 to 13. Here, the blast polishing slurries 1 to 13 had a pH of 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 corresponds to 50% of the total particle volume (Dv50%), and the cumulative particle volume from the large particle diameter side is 3 of the total particle volume. %, and a particle diameter (Dv0.1%) in which the cumulative particle volume from the large particle diameter side corresponds to 0.1% of the total particle volume. The results are shown in Table 2 below.

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

<<Measurement>>
After ultrasonic treatment of each sample under the above conditions, particle size distribution (equivalent diameter) was measured within 3 minutes under the following measurement conditions.

(Measurement condition)
Measuring device: Microtrac MT3000II (manufactured by Microtrac 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: Volume circulator condition Flow velocity: 50%
Ultrasonic output: 40W
Ultrasonic time: 240 seconds.

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

(Blasting conditions)
Equipment: Mipot MBM-2 (Mcco Co., Ltd.)
Work: Alkali-free glass (30mm x 30mm, thickness 3mm)
Nozzle opening to work distance: 0.5 mm
Nozzle position: Fixed nozzle opening shape: Circular (diameter 1 mm)
Nozzle angle: Right angle (90°) to the workpiece (jetting with the nozzle position fixed)
Air pressure: 0.4 MPa.

With respect to the work that was blasted under the above conditions, the reduced mass (g) and the surface roughness (ΔRa) of the work mass after processing were evaluated. The processing time was 10 seconds in the following (reduced mass of the work mass after processing) and 1 second in the following (surface roughness). The results are shown in Table 2 below.

(Reduced work mass after machining: Machining efficiency)
The reduced mass (W(g)) of the work mass after machining with respect to the work mass before machining was measured. A large reduction mass (W(g)) of the work mass after machining means that a larger amount (larger) is polished, and the machining efficiency is high.

(Surface roughness)
“Ra” indicating the surface roughness on the processed surface was measured for the work before and after processing, and a value obtained by subtracting Ra before processing from Ra after processing was defined as ΔRa. The lower the value of ΔRa, the flatter the processed surface is. 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. The measurement condition (viewing angle) of the non-contact profilometer was 280 μm×210 μm.

(Clog)
The presence or absence of clogging was evaluated using blast polishing slurries 1 to 13, respectively. At this time, the evaluation of clogging was performed by measuring the flow rate (recovery amount) of the slurry as follows. First, under the above-mentioned blasting conditions, the blasting apparatus was operated for 1 minute without installing a work, and the amount (weight) of the slurry collected by the slurry collection container was measured. The operation was set as one set and 16 sets were performed. The average (A) of the slurry collection amounts (weight) of the first three sets and the average (B) of the slurry collection amounts (weight) of the last three sets were compared to evaluate the ease of clogging of the slurry. When changing the blast polishing slurry, the inside of the processing apparatus was washed and replaced with water before each evaluation. The evaluation criteria are as follows.

(Evaluation criteria for clogging)
X: The reduction rate of the average (B) of the collected amounts with respect to the average (A) of the collected amounts is 10% or more. O: The reduction rate of the average (B) of the collected amounts with respect to the average (A) of the collected amounts is 10. %Less than.

From Table 2 above, according to the slurry for blast polishing 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, it is possible to suppress clogging of the processing device (the flow path of the blast polishing slurry such as the pipe and the nozzle).

1 Polishing object,
4 Slurry for blast polishing,
7 injection nozzles,
100 Blasting machine.

Claims (7)

First particles having a Mohs hardness of 8 or more,
Second particles having a Mohs hardness smaller than that of the first particles;
And a dispersion medium,
The second particles include zircon particles,
The particle diameter (Dv50%) corresponding to 50% of the total particle volume when the cumulative particle volume from the large particle diameter side, which was measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W, was 1. 2 μm or more and 4.5 μm or less, and the particle diameter (Dv3%) corresponding to 3% of the total particle volume of the particles from the large particle diameter side is 3 μm or more and 7 μm or less,
Blast polishing slurry having a pH of 3 or more and 10 or less. Content of the first particles, the second greater than the content of the particles, blast polishing slurry of claim 1. The blast polishing slurry according to claim 1 or 2 , wherein the first particles are alumina particles. Is for glass processing, blast polishing slurry according to any one of claims 1-3. A particle diameter (Dv 0.1%) in which the cumulative particle volume measured from the large particle diameter side of the particle measured after performing an ultrasonic dispersion treatment for 120 seconds at an output of 40 W (Dv 0.1%) ) is 15μm or less, according to claim 1 blast polishing slurry according to any one of 4. Is 45 wt% or less than 10 wt% content of the particles, blast polishing slurry according to any one of claims 1-5. Polyacrylic acid, polyacrylamide or further comprising acrylamide-acrylic acid sodium copolymer, blast polishing slurry according to any one of claims 1 to 6.