Polishing composition and polishing method

Abstract

The present invention provides a polishing composition which has excellent processing force. The present disclosure relates to a polishing composition which comprises abrasive grains, water, and a hydrophobic dispersion medium, wherein if D10, D50, and D90 are respective particle diameters at which the cumulative volume from the largest particle size is 10 vol%, 50 vol%, and 90 vol% in the volume-based particle size distribution of the abrasive grains, the particle size distribution width of the abrasive grains, (D10 - D90) / D50, is 1.55 to 10.0 inclusive, and the flatness degree of the abrasive grains having a particle diameter larger than D10 is more than 3.3 and less than 30.

Description

Polishing composition and polishing method

[0001] The present invention relates to a polishing composition and a polishing method.

[0002] Resin coating films are formed on the surface of substrates to protect them from the surrounding environment. There are many types of resin coating materials, such as urethane resins, epoxy resins, polyester resins, alkyd resins, acrylic resins, fluororesins, melamine resins, silicone resins, phenolic resins, vinyl acetate resins, natural oil resin paints, and chlorinated rubber resins. In recent years, it has been proposed to impart functions to these resin coating films according to the intended purpose, such as high gloss, water resistance, chemical resistance, and abrasion resistance.

[0003] For example, the painted surface of an automobile body is generally painted multiple times, starting from the body surface, with a primer coat, a middle coat, and a top coat. Painting not only serves to protect the surface from sunlight, wind, and rain, protecting it from scratches, rust, and other damage, thereby extending its life, but also to enhance its aesthetic appearance, including gloss and smoothness. Top coats, in particular, are typically formed using a two-layer resin coating consisting of a base color coat that determines the color of the automobile and a clear coat that imparts a beautiful gloss to the painted surface.

[0004] In recent years, fiber-reinforced plastics (FRP) materials have been widely used in the structures of ships, aircraft, etc. FRP materials are materials reinforced by embedded fibers. Glass fiber-reinforced plastics (GFRP), carbon fiber-reinforced plastics (CFRP), and aramid fiber-reinforced plastics (aramid fiber composites, AFC) are the most frequently used.

[0005] It is known that the surface of these FRP materials is coated with a resin coating called a gel coat having a thickness of several hundred microns, which functions as a protective layer (for example, JP 2010-76277 A).

[0006] Such resin coatings (e.g., clear coated surfaces, gel coated surfaces, etc.) are polished for the purpose of flattening during painting, removing scratches that occur during use, uniforming the paint when repainting after scratch repair, eliminating whitening due to aging, etc. (e.g., JP 2000-60755 A, JP 2012-251099 A). A known method for polishing a painted surface is to use a buff (polishing wheel) and a polisher (polishing machine) attached to rotate the buff, with a polishing composition interposed between the painted surface and the buff, and then rotate the buff with the polisher.

[0007] When polishing a resin coating (e.g., a clear coating, a gel coat coating, etc.), it is required that the polished surface is free of scratches, that the color of the coating surface appears clear, that the surface does not appear whitish due to fine scratches on the surface caused by polishing, and that the polished surface does not have any waviness. In polishing such resin coatings, further improvements in processing force are required. Processing force refers to the force that physically removes the workpiece, such as the force with which abrasive grains create fine scratches on the surface of the workpiece.

[0008] Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polishing composition having excellent processing power.

[0009] In order to solve the above problems, the present inventors have conducted extensive research and have found that abrasive grains, water, and a hydrophobic dispersion medium are included, and that the particle diameters at which the cumulative volume from the large particle side in the volume-based particle size distribution of the abrasive grains is 10 volume %, 50 volume %, and 90 volume %, respectively, are defined as D １０ , D ５０ , and D ９０ When the particle size distribution width (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０ The inventors have found that the above problems can be solved by a polishing composition in which the abrasive grains having a larger particle diameter have a flatness of more than 3.3 and less than 30, and have thus completed the present invention.

[0010] The following describes in detail the embodiments of the present invention. The embodiments described herein are merely illustrative examples for embodying the technical concept of the present invention and are not intended to limit the present invention. Therefore, all other possible embodiments, methods of use, and operational techniques conceivable by those skilled in the art without departing from the spirit of the present invention are within the scope and spirit of the present invention, as well as within the scope of the claims and their equivalents. The embodiments described herein can be arbitrarily combined to produce other embodiments. Furthermore, in this specification, the range "X to Y" means "X or more and Y or less," and "weight," "weight %," "mass %," and "parts by weight" and "parts by mass" are treated as synonyms. Unless otherwise specified, in this specification, operations and measurements of physical properties are performed at room temperature (20°C to 25°C) and a relative humidity of 40% RH to 50% RH.

[0011] <Polishing Composition> One embodiment of the present invention is a polishing composition comprising abrasive grains, water, and a hydrophobic dispersion medium, wherein the particle diameters at which the cumulative volume from the large particle side in a volume-based particle size distribution of the abrasive grains is 10 volume %, 50 volume %, and 90 volume %, respectively, are defined as D １０ , D ５０ , and D ９０ When the particle size distribution width (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０ The polishing composition has a flatness of more than 3.3 and less than 30 for the abrasive grains having a larger particle size. The polishing composition according to this embodiment having such a configuration has excellent processing power when polishing an object to be polished as rough polishing or finish polishing. That is, according to one embodiment of the present invention, a polishing composition having excellent processing power is provided. Note that "excellent processing power" means, for example, that in an evaluation of processing power for removing scratches (eliminating scratches) after polishing, the time required for scratches to be removed is short.

[0012] The polishing composition according to the present invention has a particle diameter D where the abrasive grains have a specific particle size distribution and the cumulative volume of the larger grains is 10% by volume. １０The researchers discovered that the flat shape of abrasive grains (hereinafter also referred to as "coarse grains") having a particle diameter larger than 1000 mm significantly improves the processing power. Although the details of this mechanism are unclear, it is believed that the coarse grains and small particles other than the coarse grains (i.e., grain diameter D １０ It is believed that the balance between the proportion of coarse particles (abrasive grains having the particle diameter below) and the shape of the coarse particles contained at less than 10% by volume leads to improved processing power. The flat shape of the coarse particles makes them less likely to roll during the polishing process, and is thought to increase the processing power applied to the object to be polished. Furthermore, the presence of small particles near the coarse particles allows the small particles to act efficiently, improving processing power. On the other hand, if the content of coarse particles is high or the particle diameter is too large, there is a risk of a deterioration in the finished surface. The present invention has discovered a configuration that can maximize the effect on processing power induced by the size and shape of these abrasive grains.

[0013] The above mechanism is based on speculation, and the present invention is not limited to the above mechanism in any way.

[0014] Hereinafter, each component contained in the polishing composition of this embodiment will be described.

[0015] [Abrasive Grains] The polishing composition according to this embodiment contains abrasive grains, which have the function of mechanically polishing an object to be polished.

[0016] The abrasive grains used in the polishing composition according to the present embodiment have particle diameters at which the cumulative volume from the large particle side is 10 vol%, 50 vol%, and 90 vol%, respectively, in the particle size distribution on a volume basis measured by a capillary electrical resistance method. １０ , D ５０ , and D ９０ When the particle size distribution width of the abrasive grains (D １０ -D ９０ ) / D ５０ The particle size distribution width (D １０ -D ９０ ) / D ５０ is the average secondary particle diameter of the abrasive grains and the particle size distribution width (D １０ -D ９０ ) where the particle size distribution width (D１０ -D ９０ ) / D ５０ The particle size distribution width (D) of 1.55 or more and 10.0 or less indicates that a somewhat broad particle size distribution is more suitable than a sharp particle size distribution. １０ -D ９０ ) / D ５０ When the particle size distribution width (D) of the abrasive grains is within the above range, the ratio of the coarse particles to the small particles other than the coarse particles acts in a balanced manner on the processing force, and as a result, the processing force can be improved. １０ -D ９０ ) / D ５０ If the particle size distribution width (D) of the abrasive grains is less than 1.55, the abrasive grains have a relatively sharp particle size distribution, and the frictional force that the abrasive grains impart to the object to be polished is insufficient, which takes time to remove scratches and reduces the processing power. １０ -D ９０ ) / D ５０ If the particle size distribution exceeds 10.0, the abrasive grains will have a broad particle size distribution, and the frictional force applied to the workpiece by the abrasive grains will be excessive, resulting in a poor finished surface.

[0017] In the polishing composition according to the present invention, the particle size distribution width (D １０ -D ９０ ) / D ５０ is preferably 1.60 or more, more preferably 2.00 or more, even more preferably 3.00 or more, particularly preferably 4.00 or more, and most preferably 5.00 or more, from the viewpoint of processing power. １０ -D ９０ ) / D ５０ From the viewpoint of the finished surface, the particle size distribution width (D １０ -D ９０ ) / D ５０ is preferably 1.60 or more and 9.00 or less, more preferably 2.00 or more and 8.00 or less, and particularly preferably 4.00 or more and 7.00 or less. １０-D ９０ ) / D ５０ is 1.56 or more, 1.58 or more, 1.59 or more, or 1.60 or more. １０ -D ９０ ) / D ５０ is 7.00 or less, 6.00 or less, 5.00 or less, or 4.50 or less. １０ -D ９０ ) / D ５０ According to another embodiment, the particle size distribution width (D １０ -D ９０ ) / D ５０ The particle size distribution width (D １０ -D ９０ ) / D ５０ When the content of the coarse particles is within the above range, the ratio of the coarse particles to the small particles other than the coarse particles acts in a well-balanced manner on the processing force, and as a result, the processing force can be further improved.

[0018] The abrasive grains used in the polishing composition according to the present embodiment are D １０ and D ９０ The ratio (D １０ / D ９０ ) is preferably 3.6 or more and 50 or less, more preferably 4.0 or more and 30 or less, particularly preferably 4.5 or more and 20 or less, and most preferably 5.0 or more and 18 or less. １０ / D ９０ is 3.5 or more and 30 or less, 4.0 or more and 20 or less, 5.0 or more and 18.0 or less, 5.0 or more and 17.0 or less, 6.0 or more and 20.0 or less, 6.0 or more and 18.0 or less, 3.0 or more and 8.0 or less, or 3.0 or more and 7.0 or less. １０ / D ９０ is 8.0 or more and 20 or less, 10 or more and 30 or less, 10 or more and 20 or less, or 10 or more and 18.0 or less. １０ / D ９０ When the particle diameter is within the above range, the mechanical action of the particles increases, and the desired effect of the present invention is more effectively achieved.

[0019] D of the abrasive grains used in the polishing composition according to the present embodiment １０ is preferably 6.0 μm or more, more preferably 6.5 μm or more, even more preferably 7.0 μm or more, particularly preferably 7.5 μm or more, and most preferably 8.0 μm or more. １０ is preferably 40.0 μm or less, more preferably 35.0 μm or less, even more preferably 33 μm or less, particularly preferably 32.0 μm or less, and most preferably 30.0 μm or less. １０ is preferably 6.0 μm or more and 40.0 μm or less, more preferably 6.5 μm or more and 35.0 μm or less, even more preferably 7.0 μm or more and 33 μm or less, particularly preferably 7.5 μm or more and 32.0 μm or less, and most preferably 8.0 μm or more and 30.0 μm or less. １０ According to one embodiment, the value of D of the abrasive grains is 7.0 μm or more and 12.0 μm or less, or 8.0 μm or more and 12.0 μm or less. １０ is 25.0 μm or less, 20.0 μm or less, 15 μm or less, 13.0 μm or less, or 12.0 μm or less. １０ is 10.0 μm or more, 12.0 μm or more, 15 μm or more, 18.0 μm or more, or 20.0 μm or more. １０ When the particle diameter is within the above range, the mechanical action of the particles increases, and the desired effect of the present invention is more effectively achieved.

[0020] D of the abrasive grains used in the polishing composition according to the present embodiment ５０ The diameter of the abrasive grains is preferably 0.05 μm or more and 15 μm or less. ５０ corresponds to the secondary particle diameter. ５０ is preferably 2.5 μm or more, more preferably 3.0 μm or more, even more preferably 3.5 μm or more, particularly preferably 4.0 μm or more, and most preferably 4.3 μm or more. ５０is preferably 8.0 μm or less, more preferably 7.5 μm or less, even more preferably 7.0 μm or less, particularly preferably 6.5 μm or less, and most preferably 6.0 μm or less. That is, D of the abrasive grains ５０ is preferably 2.5 μm or more and 8.0 μm or less, more preferably 3.0 μm or more and 7.5 μm or less, even more preferably 3.5 μm or more and 7.0 μm or less, particularly preferably 4.0 μm or more and 6.5 μm or less, and most preferably 4.3 μm or more and 6.0 μm or less. ５０ The value of D of the abrasive grains is 4.0 μm or more and 7.0 μm or less, or 4.0 μm or more and 6.0 μm or less. ５０ When the particle diameter is within the above range, the mechanical action of the particles increases, and the desired effect of the present invention is more effectively achieved.

[0021] The abrasive grains used in the polishing composition according to the present invention are D ９０ is preferably 0.1 μm or more, more preferably 0.5 μm or more, even more preferably 1.0 μm or more, particularly preferably 1.2 μm or more, and most preferably 1.5 μm or more. ９０ is preferably 5.0 μm or less, more preferably 4.0 μm or less, even more preferably 3.5 μm or less, particularly preferably 3.0 μm or less, and most preferably 2.5 μm or less. ９０ is preferably 0.1 μm or more and 5.0 μm or less, more preferably 0.5 μm or more and 4.0 μm or less, even more preferably 1.0 μm or more and 3.5 μm or less, particularly preferably 1.2 μm or more and 3.0 μm or less, and most preferably 1.5 μm or more and 2.5 μm or less. ９０ The value of D of the abrasive grains is 0.5 μm or more and 3.0 μm or less, 0.5 μm or more and 2.0 μm or less, or 1.0 μm or more and 2.5 μm or less. ９０ When the particle diameter is within the above range, the mechanical action of the particles increases, and the desired effect of the present invention is more effectively achieved.

[0022] In this specification, the particle size distribution of the abrasive grains is based on the pore electrical resistance method, specifically the International Standard ISO 13319:2021 Determination of particle size distributions - Electrical sensing zone method. Examples of particle size and measuring devices include the measuring devices described in the Examples. In addition, in measurements based on the International Standard ISO (ISO 13319:2021), an aperture (pore tube) having a diameter corresponding to the particle size is used.

[0023] The abrasive grains used in the polishing composition of this embodiment may have two or more maximum points of different particle diameters in the particle size distribution on a volume basis measured by a pore electrical resistance method. The number of maximum points may be 1, 2, 3, or 4 or more. In the polishing composition of this embodiment, the number of maximum values ​​in the particle size distribution on a volume basis is preferably 1 or more and 5 or less, more preferably 1 or more and 4 or less, even more preferably 1 or more and 3 or less, and particularly preferably 1 or more and 2 or less.

[0024] In the polishing composition according to the present embodiment, D calculated based on the particle size distribution measured by the pore electrical resistance method １０ It is characterized by the shape of the abrasive grains (coarse grains) with larger particle diameters. １０ Abrasive grains having a larger particle size have a flatness of more than 3.3 and less than 30. D １０ When the flatness of the abrasive grains having a larger particle diameter is within the above range, the coarse particles can efficiently apply friction to the object to be polished, thereby improving the processing power. １０ If the flatness of the abrasive grains having a larger particle diameter is 3.3 or less, the shape of the coarse particles becomes relatively close to a sphere, and the coarse particles cannot efficiently apply friction to the object to be polished, resulting in a decrease in processing power. １０ If the flatness of abrasive grains with larger particle diameters is 30 or more, the shape of the coarse particles will be thin and flat, and the coarse particles may break down when colliding with the object to be polished, or may become lodged in the object to be polished, leaving large polishing marks, etc., making it impossible to impart uniform friction and reducing the processing power.

[0025] In the polishing composition according to the present embodiment, １０ The flatness of the abrasive grains having a larger particle size (coarse particles) is preferably 3.5 or more, more preferably 4.0 or more, even more preferably 4.5 or more, particularly preferably 5.0 or more, and most preferably 5.5 or more. １０ The flatness of the abrasive grains having a larger particle size is preferably 25 or less, more preferably 20 or less, even more preferably 10 or less, particularly preferably 8 or less, and most preferably less than 7. That is, D １０ The flatness of the abrasive grains having a larger particle size is preferably 3.5 or more and 25 or less, more preferably 4.0 or more and 20 or less, even more preferably 4.5 or more and 10 or less, particularly preferably 5.0 or more and 8 or less, and most preferably 5.5 or more and less than 7. In one embodiment, D １０ The flatness of the abrasive grains having a larger particle size is 3.5 or more and 10 or less, 3.5 or more and 8.0 or less, or 4.0 or more and less than 7.0. When the flatness of the abrasive grains is within the above range, the coarse particles can efficiently apply friction to the object to be polished, further improving the processing power.

[0026] In the polishing composition according to the present embodiment, D calculated based on the particle size distribution measured by the pore electrical resistance method １０ The circularity of the abrasive grains having a larger particle size (coarse particles) is preferably 0.45 or more, more preferably 0.50 or more, even more preferably 0.55 or more, particularly preferably 0.60 or more, and most preferably 0.65 or more. １０ The circularity of the abrasive grains having a larger particle size is preferably 0.92 or less, more preferably 0.90 or less, even more preferably 0.89 or less, particularly preferably 0.88 or less, and most preferably 0.85 or less. That is, D １０The circularity of the abrasive grains having a larger particle size is preferably 0.45 or more and 0.92 or less, more preferably 0.50 or more and 0.90 or less, even more preferably 0.55 or more and 0.89 or less, particularly preferably 0.60 or more and 0.88 or less, and most preferably 0.65 or more and 0.85 or less. １０ The circularity of the abrasive grains having larger particle sizes is greater than 0.6. １０ The circularity of abrasive grains having larger particle diameters is 0.88 or less, 0.85 or less, 0.82 or less, 0.80 or less, and 0.78 or less. When the circularity of the abrasive grains is within the above range, the coarse particles can efficiently apply friction to the object to be polished, and the processing power can be further improved. Here, it is considered that by defining the shape of the abrasive grains not only by the flatness but also by the circularity, the two-dimensional shape (circularity) and three-dimensional shape (flatness) of the coarse particles can be grasped. Therefore, according to one embodiment, in the polishing composition of this embodiment, D calculated based on the particle size distribution １０ The abrasive grains having a larger particle size have a flatness of more than 3.3 and less than 30, and a circularity of 0.45 or more and 0.88 or less. １０ The abrasive grains having a larger particle size have a flatness of more than 3.3 and less than 30, and a circularity of more than 0.60 and not more than 0.88.

[0027] Here, D calculated based on the particle size distribution １０A method for calculating abrasive grains having a larger particle size (coarse particles) will be described. Specifically, images of abrasive grains are observed with a scanning electron microscope using a polishing composition or an aqueous abrasive dispersion added to the polishing composition during preparation. Specifically, the polishing composition or aqueous abrasive dispersion is dispersed in alcohol (e.g., ethanol), dried, and then placed in a scanning electron microscope (SEM). Electron beam irradiation is performed at 10 kV, and the observation field is photographed at a magnification of 500 to 200,000 times. Several similar SEM images are taken of the same sample (polishing composition or aqueous abrasive dispersion) as SEM images. For each SEM image, image analysis software (WinRoof2021) (manufactured by Mountec Co., Ltd.) is used to analyze 100 or more particles in the SEM image, and the projected area equivalent circle diameter (the diameter of a circle having the same area as the projected area of ​​the particle) of each particle is determined. The projected area equivalent circle diameter of each particle is calculated, and this value is used as the equivalent circle diameter d of each particle. Ｐ In addition, the equivalent circle diameter d Ｐ The particles used in the calculation are all particles in the captured SEM image. The circle-equivalent diameter d obtained by the SEM image analysis is Ｐ is regarded as the same value as the particle diameter measured by the pore electrical resistance method, for example, using a particle size distribution measuring device Multisizer 4e, and D １０ Larger circle equivalent diameter d Ｐ Particles having "D １０ Larger particles (D １０ abrasive grains with larger particle diameters).

[0028] D １０ The flatness of abrasive grains with larger particle diameters (coarse particles) is shown in the SEM image as "D １０ Specifically, in the SEM image, the "D １０The major axis l (Feret horizontal diameter), minor axis b (Feret vertical diameter), and thickness t of particles corresponding to "larger particles" are measured. Each particle in the SEM image is visually observed, and when the particle is considered as a rectangular parallelepiped, the longest side of the three sides is taken as the major axis l, the next longest side as the minor axis b, and the shortest side as the thickness t. Using the obtained major axis l (Feret horizontal diameter) and thickness t, the flatness of each particle is calculated using the following formula, and the average value is taken as the flatness: Flatness = l / t (l = major axis, t = thickness).

[0029] D １０ The circularity of abrasive grains with larger particle diameters (coarse particles) is shown in the SEM image as "D １０ Specifically, in the SEM image, the "D １０ The area S and perimeter L of the particle corresponding to the "larger particle" Ｃ The circularity of each particle is calculated using the following formula, and the average value is taken as the circularity: Circularity = 4πS / L Ｃ ２ (S = area of ​​circle, L Ｃ = perimeter).

[0030] D １０ The major axis (Ferret's horizontal diameter) of the abrasive grains having a larger particle diameter (coarse particles) is preferably 8.0 μm or more, more preferably 10 μm or more, even more preferably 12 μm or more, particularly preferably 13 μm or more, and most preferably 15 μm or more. １０ The major axis (Ferret's horizontal diameter) of the abrasive grains having a larger particle size is preferably 50 μm or less, more preferably 45 μm or less, even more preferably 42 μm or less, particularly preferably 40 μm or less, and most preferably 38 μm or less. １０ The major axis (Ferret's horizontal diameter) of the abrasive grains having a larger particle size is 40 μm or less, 28 μm or less, 24 μm or less, 22 μm or less, or 20 μm or less. １０ When the major axis (Ferret's horizontal diameter) of the abrasive grains having a larger particle diameter is within the above range, the mechanical action of the grains increases, and the desired effect of the present invention is more effectively exhibited.

[0031] D １０ The minor axis (Ferret's perpendicular diameter) of the abrasive grains having a larger particle diameter (coarse particles) is preferably 5.0 μm or more, more preferably 6.0 μm or more, even more preferably 7.0 μm or more, particularly preferably 8.0 μm or more, and most preferably 10 μm or more. １０ The minor axis (Ferret's perpendicular diameter) of the abrasive grains having a larger particle size is preferably 40 μm or less, more preferably 38 μm or less, even more preferably 35 μm or less, particularly preferably 32 μm or less, and most preferably 30 μm or less. １０ The minor axis (Ferret's perpendicular diameter) of the abrasive grains having a larger particle size is 35 μm or less, 22 μm or less, 18 μm or less, 15 μm or less, or 14 μm or less. １０ When the minor axis (Ferret's perpendicular diameter) of the abrasive grains having a larger particle diameter is within the above range, the mechanical action of the grains increases, and the desired effect of the present invention is more effectively exhibited.

[0032] D １０ The thickness of the abrasive grains having a larger particle diameter (coarse particles) is preferably 0.5 μm or more, more preferably 1.0 μm or more, even more preferably 1.5 μm or more, particularly preferably 2.0 μm or more, and most preferably 2.5 μm or more. １０ The thickness of the abrasive grains having a larger particle size is preferably 10 μm or less, more preferably 9 μm or less, even more preferably 8 μm or less, particularly preferably 7.5 μm or less, and most preferably 7 μm or less. １０ The thickness of the larger grain size abrasive grains is 10 μm or less, 8 μm or less, 6 μm or less, 5 μm or less, or 4 μm or less. １０ When the thickness of the abrasive grains having a larger particle diameter is within the above range, the mechanical action of the grains increases, and the desired effect of the present invention is more effectively achieved.

[0033] Specific examples of abrasive grains used in the polishing composition according to this embodiment include metal oxides such as aluminum oxide (alumina), cerium oxide (ceria), zirconium oxide, titanium oxide (titania), tin oxide, and manganese oxide; semi-metal oxides such as silicon oxide (silica); metal carbides such as titanium carbide; semi-metal carbides such as silicon carbide; metal nitrides such as titanium nitride; semi-metal nitrides such as silicon nitride; metal borides such as titanium boride and tungsten boride; zircon (ZrSiO ４ Examples of the abrasive grains include silicate compounds such as quartz, diamond, etc. These abrasive grains may be used alone or in combination. Commercially available abrasive grains or synthetic abrasive grains may be used.

[0034] Among these abrasive grains, at least one selected from the group consisting of metal oxides and metal carbides is preferred, with metal oxides being more preferred, and at least one of aluminum oxide (alumina), cerium oxide, and zirconium oxide being even more preferred, with aluminum oxide being particularly preferred, and a mixture of alumina and zirconium being also preferably used, from the viewpoint that grains with various particle sizes are readily available and excellent processing power can be obtained.

[0035] Furthermore, among aluminum oxides, those containing an α-phase or a transition state crystalline phase, such as a θ-phase, δ-phase, or γ-phase, which is in the process of becoming the α-phase, are preferred. Aluminum oxide containing the α-phase or θ-phase is preferred, and aluminum oxide containing the α-phase is more preferred. It is believed that there is an optimal range for the α-phase depending on the degree of α-phase formation. Generally, the α-phase crystal structure is considered to be the hardest, but it is estimated that sufficient sintering at high temperatures to achieve the α-phase results in the particle shape becoming rounded and the processing strength decreasing. The α-phase ratio serves as a reference value for expressing the degree of α-phase contained in aluminum oxide. The preferred lower limit of the α-phase ratio is 50% or more. The lower limit of the α-phase ratio is more preferably 60% or more, even more preferably 65% ​​or more, and particularly preferably 70% or more. The preferred upper limit of the α-phase ratio is 100% or less. The upper limit of the α-phase ratio is more preferably 99% or less, even more preferably 98% or less, and particularly preferably 97% or less. That is, the alpha conversion rate of aluminum oxide is preferably 50% or more and 100% or less, more preferably 60% or more and 99% or less, even more preferably 65% ​​or more and 98% or less, and particularly preferably 70% or more and 97% or less. By setting the alpha conversion rate within the above preferred range, improvement in processing power, i.e., shortening of scratch removal time, is expected. The alpha conversion rate of aluminum oxide particles can be calculated from the integrated intensity ratio of the (113) plane diffraction line by X-ray diffraction measurement using an X-ray diffractometer (Ultima-IV, manufactured by Rigaku Corporation).

[0036] In the polishing composition according to the present embodiment, the specific surface area of ​​the abrasive grains is not particularly limited, but may be, for example, 0.1 m ２ The specific surface area of ​​the abrasive grains can be calculated by the method described in the Examples below.

[0037] According to one embodiment, in the polishing composition according to this embodiment, the abrasive grains have a specific surface area of ​​0.1 m ２ / g or more 30m ２ / g (preferably less than 1m ２ / g or more 20m ２ / g or less, more preferably 3m ２ / g or more 15m ２ / g or less, more preferably 4m ２ / g or more 10m ２Such abrasive grains may be prepared by, for example, processing commercially available abrasive grains and adjusting the specific surface area as appropriate, or by mixing a plurality of commercially available abrasive grains and adjusting the mixing ratio as appropriate so that the specific surface area falls within the above range.

[0038] According to one embodiment, in the polishing composition according to this embodiment, the specific surface area of ​​the abrasive grains is 0.1 m ２ / g or more 30m ２ / g (preferably less than 1m ２ / g or more 20m ２ / g or less, more preferably 3m ２ / g or more 15m ２ / g or less, more preferably 4m ２ / g or more 10m ２ / g or less). Therefore, when the abrasive grains contained in the polishing composition as a whole have the above specific surface area (when the mixing ratio of the abrasive grains is appropriately adjusted so that the specific surface area falls within the above range), the mechanical action of the particles is improved, and the expected effects of the present invention are more effectively achieved. When the polishing composition contains two or more types of abrasive grains, the overall specific surface area of ​​the abrasive grains contained in the polishing composition is calculated as a weighted average from the compounding ratio and specific surface area of ​​each abrasive grain contained in the polishing composition.

[0039] The abrasive grains preferably have a water absorption capacity of 10 mL / 100 g or more. The water absorption capacity of the abrasive grains can be calculated by the method described in the Examples below.

[0040] According to one embodiment, the abrasive grains contain abrasive grains having a water absorption of 15 mL / 100 g or more (preferably 20 mL / 100 g or more, more preferably 22 mL / 100 g or more, even more preferably 25 mL / 100 g or more, particularly preferably 30 mL / 100 g or more, and most preferably 35 mL / 100 g or more). The upper limit of the water absorption of such abrasive grains is not particularly limited, but is preferably 500 mL / 100 g or less, more preferably 450 mL / 100 g or less, even more preferably 400 mL / 100 g or less, particularly preferably 350 mL / 100 g or less, and most preferably 300 mL / 100 g or less. When the polishing composition according to this embodiment contains abrasive grains having a water absorption of 10 mL / 100 g or more, the mechanical action of the particles can be improved, and the desired effects of the present invention can be further exerted. In particular, when the polishing composition of this embodiment contains abrasive grains with a water absorption of 15 mL / 100 g or more, the mechanical action of the particles is improved, and more excellent effects can be achieved in removing waviness from resin coatings such as clear coats.

[0041] According to one embodiment, the abrasive grains have a water absorption of 10 mL / 100 g to 500 mL / 100 g, 15 mL / 100 g to 500 mL / 100 g, 20 mL / 100 g to 500 mL / 100 g, 20 mL / 100 g to 400 mL / 100 g, 20 mL / 100 g to 350 mL / 100 g, 20 mL / 100 g to 300 mL / 100 g, 22 mL / 100 g to 350 mL / 100 g, 25 mL / 100 g to 500 mL / 100 g, 25 mL / 100 g to 400 mL / 100 g, 0g or less, 25mL / 100g to 350mL / 100g, 25mL / 100g to 300mL / 100g, 30mL / 100g to 500mL / 100g, 30mL / 100g to 400mL / 100g, 30mL / 100g to 350mL / 100g, 30mL / 100g to 100mL / 100g, 35mL / 100g to 500mL / 100g, 35mL / 100g to 400mL / 100g, or 35mL / 100g to 300mL / 100g.

[0042] According to one embodiment, in the polishing composition according to this embodiment, the abrasive grains have a diameter of 0.2 m ２In one embodiment, in the polishing composition according to this aspect, the abrasive grains include abrasive grains (preferably aluminum oxide or silicon oxide) having a water absorption of 20 mL / 100 g or more.

[0043] The lower limit of the content of abrasive grains in the polishing composition is preferably 0.1 mass % or more, more preferably 0.5 mass % or more, even more preferably 1 mass % or more, particularly preferably 3 mass % or more, and most preferably 5 mass % or more, based on the total mass of the polishing composition. By making the content of abrasive grains 0.1 mass % or more, the processing force can be appropriately controlled, and the processing force can be further improved in both rough polishing and finish polishing.

[0044] The upper limit of the content of abrasive grains in the polishing composition is preferably 60 mass % or less, more preferably 50 mass % or less, even more preferably 45 mass % or less, particularly preferably 40 mass % or less, and most preferably 35 mass % or less, based on the total mass of the polishing composition. By making the content of abrasive grains 60 mass % or less, the production cost of the polishing composition is reduced, and the processing force is appropriately controlled, further improving the processing force in both rough polishing and finish polishing.

[0045] According to one embodiment, the abrasive grains are contained in an amount of 5% by mass or more and 50% by mass or less, or 10% by mass or more and 45% by mass or less, based on the total mass of the polishing composition.

[0046] As described above, the abrasive grains used in the polishing composition according to the present embodiment have a particle size distribution width (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０The flatness of the abrasive grains having larger particle diameters is more than 3.3 and less than 30. For example, commercially available abrasive grains can be crushed to appropriately adjust the particle size distribution and the shape of the coarse particles, or a plurality of commercially available abrasive grains can be mixed and the mixing ratio can be appropriately adjusted so that the particle size distribution and the shape of the coarse particles fall within the above range. For example, the abrasive grains used to adjust the particle size distribution and the shape of the coarse particles can be commercially available products such as the PWA series (e.g., PWA3, PWA5, PWA9, PWA12, PWA15, PWA20, PWA25, PWA30, PWA35, etc.) manufactured by Fujimi Incorporated; and the WA series (e.g., WA#800, WA#1000, WA#1200, WA#1500, WA#2000, WA#2500, WA#3000, etc.) manufactured by Fujimi Incorporated.

[0047] [Water] The polishing composition according to this embodiment contains water. From the viewpoint of suppressing the inhibition of the action of other components, the water is preferably water containing as few impurities as possible. Specifically, pure water or ultrapure water obtained by removing impurity ions with an ion exchange resin and then passing the water through a filter to remove foreign matter, or distilled water is preferred.

[0048] The lower limit of the water content (charge amount) in the polishing composition is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, particularly preferably 15% by mass or more, and most preferably 20% by mass or more, based on the total mass of the polishing composition.The upper limit of the water content (charge amount) in the polishing composition is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 80% by mass or less, particularly preferably 75% by mass or less, and most preferably 70% by mass or less, based on the total mass of the polishing composition.That is, the water content (charge amount) in the polishing composition is preferably 1% by mass or more and 90% by mass or less, more preferably 5% by mass or more and 85% by mass or less, even more preferably 10% by mass or more and 80% by mass or less, particularly preferably 15% by mass or more and 75% by mass or less, and most preferably 20% by mass or more and 70% by mass or less.By having the water content (charge amount) in the above range, the processing power can be improved.

[0049] According to one embodiment, the water content (charge amount) in the polishing composition is 5% by mass or more and 65% by mass or less, 10% by mass or more and 65% by mass or less, 20% by mass or more and 65% by mass or less, 5% by mass or more and 60% by mass or less, 10% by mass or more and 60% by mass or less, 20% by mass or more and 60% by mass or less, 5% by mass or more and 55% by mass or less, 10% by mass or more and 55% by mass or less, 20% by mass or more and 55% by mass or less, 5% by mass or more and 52% by mass or less, 10% by mass or more and 52% by mass or less, or 20% by mass or more and 52% by mass or less, based on the total mass of the polishing composition. When the water content (charge amount) in the polishing composition is within the above range, the mechanical action of the particles can be improved, and the desired effect of the present invention can be further enhanced. Furthermore, when the water content (charge amount) in the polishing composition is within the above range, the mechanical action of the particles can be improved, and a more excellent effect can be exhibited in terms of removing waviness from resin coating films such as clear coatings.

[0050] Here, according to one embodiment, the net water content in the polishing composition according to this embodiment is 5% by mass or more and 60% by mass or less, 10% by mass or more and 60% by mass or less, 20% by mass or more and 60% by mass or less, 5% by mass or more and 55% by mass or less, 10% by mass or more and 55% by mass or less, 20% by mass or more and 55% by mass or less, 5% by mass or more and 50% by mass or less, 10% by mass or more and 50% by mass or less, 20% by mass or more and 50% by mass or less, 5% by mass or more and 45% by mass or less, 10% by mass or more and 45% by mass or less, or 20% by mass or more and 45% by mass or less. According to one embodiment, the net water content in the polishing composition according to this embodiment can be calculated as the water content converted by taking into account the water absorption of abrasive grains. More specifically, based on the content and water absorption of abrasive grains, the net water content of the polishing composition is calculated by subtracting the amount of water absorbed by the abrasive grains from the water content (charge amount) of the polishing composition. When the net water content in the polishing composition, taking into account the water absorption of the abrasive grains, is within the above range, the mechanical action of the particles can be improved, and the expected effect of the present invention can be more effectively achieved.In addition, when the net water content in the polishing composition, taking into account the water absorption of the abrasive grains, is within the above range, the mechanical action of the particles can be improved, and a more excellent effect can be achieved in removing waviness from resin coating films such as clear coatings.In addition, the water absorption of the abrasive grains is considered for abrasive grains with a water absorption of 10 mL / 100 g or more, and does not need to be considered for abrasive grains that are in the state of an aqueous dispersion when prepared.

[0051] [Hydrophobic Dispersion Medium] The polishing composition according to this embodiment contains a hydrophobic dispersion medium. The hydrophobic dispersion medium may, for example, comprise at least one selected from the group consisting of normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons. The hydrophobic dispersion medium preferably has a vapor pressure of 0.0001 kPa or more and 2 kPa or less at 20°C. Therefore, according to one embodiment, the hydrophobic dispersion medium comprises at least one selected from the group consisting of normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons, and the vapor pressure of the hydrophobic dispersion medium at 20°C is 0.0001 kPa or more and 2 kPa or less. Hereinafter, the normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons that may be contained in the hydrophobic dispersion medium may be referred to as "organic solvents." The hydrophobic dispersion medium refers to a highly volatile compound, for example, a compound with a flash point of less than 145°C.

[0052] The hydrophobic dispersion medium may be composed of only one organic solvent, or may be a mixture of two or more organic solvents.

[0053] The hydrophobic dispersion medium and organic solvent in this embodiment are preferably those that are not easily soluble in water. The hydrophobic dispersion medium and organic solvent may be commercially available products or synthetic products.

[0054] The normal paraffin hydrocarbons, isoparaffin hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons are preferably derived from mineral oil, and may be obtained by extracting and refining components derived from mineral oil, or may be synthesized using components derived from mineral oil as raw materials (synthetic hydrocarbons derived from mineral oil). The normal paraffin hydrocarbons, isoparaffin hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons are more preferably synthetic hydrocarbons derived from mineral oil.

[0055] Examples of normal paraffin hydrocarbons include linear hydrocarbons having from 5 to 30 carbon atoms, liquid paraffin, kerosene, and diesel.

[0056] Examples of isoparaffin hydrocarbons include branched hydrocarbons having 5 to 40 carbon atoms, and liquid isoparaffin.

[0057] Examples of naphthenic hydrocarbons include cyclic hydrocarbons having from 5 to about 40 carbon atoms, such as monocyclic cycloparaffins such as cyclohexane, cyclopentane, and cyclononane; polycyclic cycloparaffins such as decalin; and alkylcycloparaffins such as methylcyclopentane, methylcyclohexane, 1-methyl-4-isopropylcyclohexane, butylcyclohexane, and methyldecalin.

[0058] Examples of terpene hydrocarbons include chain terpene hydrocarbons such as myrcene, farnesene, and citral; and cyclic terpene hydrocarbons such as menthol, cineole, pinene, limonene, α-terpinene, γ-terpinene, camphene, phellandrene, terpinene, terpinolene, p-cymene, and cedrene.

[0059] The hydrophobic dispersion medium may further contain organic solvents other than the normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons. Hereinafter, organic solvents other than normal paraffinic hydrocarbons, isoparaffinic hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons will be referred to as "other organic solvents." Examples of such other organic solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, acetone, diethyl ether, ethyl acetate, butyl acetate, triethyl citrate, acetyltributyl citrate, and acetyltriethyl citrate.

[0060] The molecular weight of the hydrophobic dispersion medium is preferably 80 or more, more preferably 100 or more, even more preferably 120 or more, and particularly preferably 140 or more. The molecular weight of the hydrophobic dispersion medium is preferably 600 or less, more preferably 500 or less, even more preferably 450 or less, and particularly preferably 400 or less. When the molecular weight of the hydrophobic dispersion medium is within the above range, the hydrophobic dispersion medium can disperse the abrasive grains well, resulting in further improved processing power. The molecular weight of the hydrophobic dispersion medium is calculated from the average carbon number and molecular structure described in the SDS etc. using the atomic weight defined by IUPAC.

[0061] Hydrophobic dispersion media (organic solvents) generally have a flash point. The flash point is the lowest temperature at which a liquid generates a sufficient concentration of vapor to instantly ignite when heated at a constant temperature and brought close to a flame. The flash point can also be said to be the lowest temperature at which the hydrophobic dispersion medium volatilizes and forms a flammable mixture with air. There are various methods for measuring flash point, depending on the purpose of the measurement and the properties of the sample. Flash point measurement methods include the closed-cell method and the open-cell method. Examples of closed-cell methods include the Tag closed-cell method (JIS K 2265-1:2007), the Seta closed-cell method (JIS K 2265-2:2007), and the Pensky-Martens closed-cell method (JIS K 2265-3:2007). Examples of open-cell methods include the Cleveland open-cell method (JIS K 2265-4:2007).

[0062] In the polishing composition according to this embodiment, the hydrophobic dispersion medium preferably has a flash point of 30°C or higher and 140°C or lower, more preferably 50°C or higher and 120°C or lower. According to one embodiment, in the polishing composition according to this embodiment, the hydrophobic dispersion medium has a flash point of 60°C or higher and 120°C or lower, 70°C or higher and 120°C or lower, 50°C or higher and 100°C or lower, 60°C or higher and 100°C or lower, more than 100°C and 140°C or lower, or 100°C or higher and 120°C or lower. When the flash point of the hydrophobic dispersion medium is within the above range, the volatility of the hydrophobic dispersion medium during polishing is appropriate, and the liquid film formed at the polishing interface is formed with an appropriate thickness, thereby further improving the expected effects of the present invention. According to one embodiment, the particle size distribution width (D １０ -D ９０) / D ５０ is 1.55 or more and 3.0 or less, and the flash point of the hydrophobic dispersion medium is more than 100° C. and 140° C. or less. １０ -D ９０ ) / D ５０ is 1.55 or more and 7.0 or less (preferably more than 3.0 and 7.0 or less), and the flash point of the hydrophobic dispersion medium is 60°C or more and 100°C or less.

[0063] In the polishing composition according to this embodiment, even when the hydrophobic dispersion medium contains two or more organic solvents, the flash point of the hydrophobic dispersion medium (FPI flash point, described below) is preferably 30° C. or higher and 140° C. or lower. In this specification, when the hydrophobic dispersion medium is composed of one organic solvent, the flash point of the hydrophobic dispersion medium means a flash point measured by any of the above methods. In addition, in this specification, when the hydrophobic dispersion medium contains two or more organic solvents, the flash point of the hydrophobic dispersion medium means a flash point calculated from the Flash-Point Blending Index (abbreviated as FPI) (hereinafter also referred to as "FPI flash point").

[0064] In one embodiment of the polishing composition according to this aspect, the hydrophobic dispersion medium contains at least one selected from the group consisting of normal paraffin hydrocarbons, isoparaffin hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons, and has a flash point of 30°C or higher and 140°C or lower.

[0065] According to one embodiment, the polishing composition of this embodiment has a particle size distribution width (D １０ -D ９０ ) / D ５０ The polishing composition according to one embodiment of the present invention comprises abrasive grains having a particle size distribution width (D １０ -D ９０ ) / D ５０ The abrasive grains have a viscosity of 1.55 or more and 7.0 or less (preferably more than 3.0 and less than 7.0) and a flatness of more than 3.3 and less than 30, water, and a hydrophobic dispersion medium having a flash point of 60°C or more and 100°C or less.

[0066] The lower limit of the content of the hydrophobic dispersion medium in the polishing composition is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, particularly preferably 10% by mass or more, and most preferably 15% by mass or more, based on the total mass (100% by mass) of the polishing composition.The upper limit of the content of the hydrophobic dispersion medium in the polishing composition is preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 50% by mass or less, particularly preferably 45% by mass or less, and most preferably 40% by mass or less, based on the total mass of the polishing composition.That is, the content of the hydrophobic dispersion medium in the polishing composition is preferably 0.5% by mass or more and 60% by mass or less, more preferably 1% by mass or more and 55% by mass or less, even more preferably 5% by mass or more and 50% by mass or less, particularly preferably 10% by mass or more and 45% by mass or less, and most preferably 15% by mass or more and 40% by mass or less, based on the total mass of the polishing composition. In a preferred embodiment of the present invention, the content of the hydrophobic dispersion medium is 15% by mass or more and 40% by mass or less, based on the total mass of the polishing composition. When the content of the hydrophobic dispersion medium is in this range, the processing power is further improved.

[0067] The content of the hydrophobic dispersion medium in the polishing composition is preferably 0.01 mol / kg or more, more preferably 0.05 mol / kg or more, even more preferably 0.1 mol / kg or more, particularly preferably 0.2 mol / kg or more, and most preferably 0.3 mol / kg or more, relative to the total mass of the polishing composition. According to one embodiment, the content of the hydrophobic dispersion medium in the polishing composition is 0.5 mol / kg or more, relative to the total mass of the polishing composition. Furthermore, the content of the hydrophobic dispersion medium in the polishing composition is preferably 10.0 mol / kg or less, more preferably 5.0 mol / kg or less, even more preferably 3.0 mol / kg or less, particularly preferably 2.0 mol / kg or less, and most preferably 1.5 mol / kg or less, relative to the total mass of the polishing composition. By the content of the hydrophobic dispersion medium being within the above range, the processing power is further improved.

[0068] [Other Components] The polishing composition according to this embodiment may contain, in addition to abrasive grains, water, and a hydrophobic dispersion medium, surfactants, oils, thickeners, emulsion stabilizers, additives, etc. Thus, the polishing composition according to this embodiment may contain, in addition to abrasive grains, water, and a hydrophobic dispersion medium, one or more other components selected from the group consisting of surfactants, oils, thickeners, emulsion stabilizers, and additives.

[0069] [Surfactant] The polishing composition according to this embodiment may contain a surfactant. The surfactant disperses or emulsifies the hydrophobic dispersion medium or water. The surfactant also serves as a dispersant that helps the abrasive grains in the polishing composition to disperse in the hydrophobic dispersion medium.

[0070] The surfactant is not particularly limited, but examples thereof include cationic surfactants, anionic surfactants, amphoteric surfactants, nonionic surfactants, etc. Among these, nonionic surfactants are preferred from the viewpoints of emulsifying power and dispersibility of abrasive grains.

[0071] Cationic surfactants can be classified into, for example, polyoxyethylene alkylamines, alkylalkanolamides, alkylamine salts, amine oxides, quaternary ammonium salts, tertiary amidoamine surfactants, etc. Specific examples of cationic surfactants include coconut amine acetate, stearyl amine acetate, lauryl dimethyl amine oxide, stearic acid dimethylaminopropylamide, alkyl trimethyl ammonium salts, alkyl dimethyl ammonium salts, alkyl benzyl dimethyl ammonium salts, etc.

[0072] Anionic surfactants can be classified into, for example, sulfates, sulfonic acids, phosphoric acids, phosphonic acids, carboxylic acids, and the like. Specific examples of anionic surfactants include alkyl sulfates, polyoxyethylene alkyl sulfates, polyoxyethylene alkyl sulfates, alkyl sulfates, alkyl ether sulfates, higher alcohol sulfates, alkyl phosphates, alkylbenzene sulfonic acids, α-olefin sulfonic acids, alkyl sulfonic acids, styrene sulfonic acids, alkyl naphthalene sulfonic acids, alkyl diphenyl ether disulfonic acids, polyoxyethylene alkyl ether acetates, polyoxyethylene alkyl ether phosphoric acids, polyoxyethylene alkyl phosphates, polyoxyethylene sulfosuccinic acids, alkyl sulfosuccinic acids, and salts of any of the above compounds. A specific example of an alkyl sulfonic acid is dodecyl sulfonic acid. Other examples of anionic surfactants include taurine surfactants, sarcosinate surfactants, isethionate surfactants, N-acyl acidic amino acid surfactants, quaternary ammonium salts of higher fatty acid salts, and acylated polypeptides.

[0073] Specific examples of amphoteric surfactants include alkyl betaines, alkylamine oxides, etc. Specific examples of amphoteric surfactants include cocobetaine, lauramidopropyl betaine, cocamidopropyl betaine, sodium lauroamphoacetate, sodium cocoamphoacetate, coconut oil fatty acid amidopropyl betaine, lauryl betaine (lauryl dimethylaminoacetic acid betaine), etc.

[0074] The nonionic surfactant is not particularly limited, but examples thereof include surfactants having a polyoxyalkylene group, such as polyoxyalkylene adducts.Specific examples of the polyoxyalkylene adducts are not particularly limited, but examples thereof include polyoxyalkylene alkyl ethers, polyoxyalkylene aryl ethers, polyoxyalkylene alkylamines, polyoxyalkylene fatty acid esters, polyoxyalkylene glycerin ether fatty acid esters, polyoxyalkylene sorbitan fatty acid esters, etc., whose hydrophobic groups have long chain lengths.Among these, from the viewpoint of lubricity during polishing, polyoxyalkylene alkyl ethers and polyoxyalkylene fatty acid esters whose hydrophobic groups have long chain lengths are preferred.

[0075] Examples of polyoxyalkylene alkyl ethers having a long chain length hydrophobic group that can be used as surfactants include polyoxyalkylene alkyl ethers having an alkyl group with more than 10 carbon atoms.

[0076] In surfactants having a polyoxyalkylene group, the oxyalkylene group constituting the polyoxyalkylene group is preferably one or more selected from an oxyethylene group and an oxypropylene group, more preferably an oxyethylene group. The average number of moles of oxyalkylene groups added is preferably 2 to 30, more preferably 4 to 20. The number of carbon atoms in the alkyl group in the polyoxyalkylene alkyl ether having a long-chain hydrophobic group is preferably 12 or more, more preferably 14 or more, even more preferably 16 or more, and preferably 30 or less, more preferably 20 or less, and even more preferably 18 or less. That is, the number of carbon atoms in the alkyl group in the polyoxyalkylene alkyl ether having a long-chain hydrophobic group is preferably 12 or more and 30 or less, more preferably 14 or more and 20 or less, and even more preferably 16 or more and 18 or less. The number of carbon atoms in the fatty acid residue in the polyoxyalkylene fatty acid ester is preferably 10 or more, more preferably 12 or more, even more preferably 14 or more, and preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. That is, the number of carbon atoms in the fatty acid residue in the polyoxyalkylene fatty acid ester is preferably 10 or more and 22 or less, more preferably 12 or more and 20 or less, and even more preferably 14 or more and 18 or less. The fatty acid residue may be saturated or unsaturated, and is preferably unsaturated.

[0077] Examples of polyoxyalkylene alkyl ether type nonionic surfactants include polyoxyethylene monoundecyl ether, polyoxyethylene monododecyl ether (polyoxyethylene monolauryl ether), polyoxyethylene didodecyl ether (polyoxyethylene dilauryl ether), polyoxyethylene monotetradecyl ether (polyoxyethylene monomyristyl ether), polyoxyethylene ditetradecyl ether (polyoxyethylene dimyristyl ether), polyoxyethylene monooleyl ether, polyoxyethylene dioleyl ether, etc. Examples of polyoxyalkylene aryl ether type nonionic surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene octylphenyl ether, polyoxyethylene dodecylphenyl ether, etc. Examples of polyoxyalkylene alkylamine type surfactants include polyoxyethylene laurylamine, polyoxyethylene stearylamine, polyoxyethylene oleylamine, etc. Examples of polyoxyalkylene fatty acid ester-type nonionic surfactants include polyoxyethylene monolaurate, polyoxyethylene monostearate, polyoxyethylene distearate, polyoxyethylene monooleate, and polyoxyethylene dioleate. Examples of polyoxyalkylene glycerin ether fatty acid ester-type nonionic surfactants include polyoxyethylene glycerin monolaurate and polyoxyethylene glycerin ether monostearate. Examples of polyoxyalkylene sorbitan fatty acid ester-type nonionic surfactants include polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopaltimate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monooleate, and polyoxyethylene sorbitan trioleate.

[0078] Further, examples of the polyoxyalkylene adducts include polyoxyethylene sorbitol trioleate, polyoxyethylene castor oil, and polyoxyethylene hydrogenated castor oil.

[0079] The nonionic surfactant preferably has an HLB of 1-18, more preferably 2-16, and even more preferably 4-15.

[0080] The molecular weight of the surfactant is not particularly limited, but is preferably less than 1,000, more preferably less than 500, and even more preferably less than 400. The molecular weight of the surfactant is preferably calculated from the chemical formula.

[0081] The surfactant may be a commercially available product or a synthetic product. The surfactant may be used alone or in combination of two or more types.

[0082] The content of the surfactant is not particularly limited, but is preferably 0.01 mass% or more and 25 mass% or less, more preferably 0.05 mass% or more and 20 mass% or less, even more preferably 0.1 mass% or more and 15 mass% or less, particularly preferably 0.5 mass% or more and 12 mass% or less, and most preferably 1 mass% or more and 10 mass% or less, based on the total mass of the polishing composition. In one embodiment, the content of the surfactant is 0.5 mass% or more and 18 mass% or less, or 0.5 mass% or more and 15 mass% or less, based on the total mass of the polishing composition. When the surfactant is contained within the above range, the stability of the emulsion in the polishing composition is increased.

[0083] The polishing composition of this embodiment preferably contains a nonionic surfactant as a surfactant, more preferably a polyoxyalkylene alkyl ether, and even more preferably a polyoxyalkylene alkyl ether having an alkyl group having 12 to 22 carbon atoms.

[0084] [Oil] The polishing composition according to this embodiment may contain an oil. The oil is a component that disperses in a hydrophobic dispersion medium and aids in emulsion stability. The oil may be in any state, such as liquid, solid, or gel, but is preferably liquid at room temperature (25°C). For example, when a solid or gel oil is used as the oil, the viscosity of the polishing composition can be improved, and the polishing composition becomes a paste-like composition. Therefore, the polishing composition according to this embodiment includes both liquid and paste polishing compositions. The oil means a substance with low volatility, such as a compound with a flash point of 145°C or higher.

[0085] Examples of oily agents include fatty acids or salts thereof; oils and fats; saturated or unsaturated petroleum hydrocarbons such as mineral oil, liquid paraffin, and olefins (excluding waxes); and waxes that are solid or semi-solid at room temperature (25°C), such as paraffin wax (also called solid paraffin) and petrolatum.

[0086] In this specification, a liquid at room temperature (25°C) refers to a substance having a viscosity of, for example, 10,000 mPa·s or less at 25°C, and a solid or semi-solid substance at room temperature (25°C) refers to a substance having a viscosity of more than 10,000 mPa·s at 25°C. Hereinafter, a semi-solid substance is included in a solid substance. Viscosity is measured using a rotational viscometer.

[0087] The polishing composition according to this embodiment may contain a fatty acid or its salt as an oil agent. The fatty acid is preferably a linear or branched fatty acid having 8 to 30 carbon atoms, more preferably a linear or branched fatty acid having 10 to 26 carbon atoms, and even more preferably a linear or branched fatty acid having 12 to 22 carbon atoms. The fatty acid may be either a saturated or unsaturated fatty acid. When the fatty acid is in the form of a salt (i.e., a fatty acid salt), examples of the cation species constituting the fatty acid salt include alkali metal cations such as lithium cation, sodium cation, and potassium cation, and alkaline earth metal cations such as magnesium cation, calcium cation, strontium cation, and barium cation. Hereinafter, the fatty acid or its salt will also be referred to as "fatty acid (salt)."

[0088] Examples of fatty acids or salts thereof include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, 12-hydroxystearic acid, undecylenic acid, isostearic acid, linoleic acid, linolenic acid, eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), behenic acid, erucic acid, tall acid, and salts thereof. The fatty acids (salts) may be used alone or in combination of two or more.

[0089] From the viewpoint of the polishing composition as a whole efficiently contributing to polishing, it is preferable that the polishing composition of this embodiment contains one or more fatty acids or salts thereof selected from the group consisting of lauric acid, oleic acid, myristic acid, palmitic acid, stearic acid, linoleic acid, and salts thereof.

[0090] The polishing composition according to this embodiment may contain a fat or oil as an oil agent. The fat or oil serves as a dispersion medium for dispersing the abrasive grains. As the fat or oil, for example, safflower oil, grape oil, evening primrose oil, walnut oil, sunflower oil, soybean oil, cottonseed oil, corn oil, wheat germ oil, rosehip oil, borage seed oil, rice bran oil, sesame oil, peanut oil, adlay oil, rapeseed oil, linseed oil, palm oil, olive oil, tung oil, castor oil, coconut oil, and hardened oils thereof can be preferably used. The fat or oil may be used alone or in combination of two or more.

[0091] The polishing composition according to this embodiment may contain saturated or unsaturated petroleum hydrocarbons (excluding waxes) as oils and fats.

[0092] The polishing composition according to this embodiment may contain a wax as an oil agent. Examples of waxes that can be preferably used include paraffin wax, microcrystalline wax, carnauba wax, montan wax, and polyethylene wax. One type of wax may be used alone, or two or more types may be used in combination.

[0093] [Thickener] The polishing composition according to this embodiment may contain a thickener. The thickener has the effect of increasing the viscosity of the polishing composition and improving its stability. Examples of the thickener used in the polishing composition according to this embodiment include inorganic compounds that are solid at room temperature (25°C); organic polymer compounds; and the like.

[0094] Examples of inorganic compounds include amorphous silica, bentonite, layered silicate compounds, etc. Examples of amorphous silica include silica gel, silica sol, precipitated silica, fumed silica, etc. Of these, the inorganic compound used as a thickener is preferably amorphous silica, more preferably precipitated silica, silica gel, or fumed silica, and even more preferably fumed silica or precipitated silica.

[0095] Examples of organic polymer compounds include synthetic thickeners such as (meth)acrylic compounds such as poly(meth)acrylic acid and sodium poly(meth)acrylate, and urethane compounds; cellulose thickeners (semi-synthetic thickeners) such as carboxymethyl cellulose and carboxyethyl cellulose; and natural thickeners such as agar, carrageenan, xanthan gum, and gum arabic.

[0096] Examples of the (meth)acrylic compound include fully neutralized compounds, partially neutralized compounds, and alkali-soluble poly(meth)acrylic acids ((meth)acrylic polymers). Of these, alkali-soluble poly(meth)acrylic acids are preferred. Alkali-soluble poly(meth)acrylic acids are also called alkali-soluble thickeners, and generally contain a high molecular weight polymer (i.e., poly(meth)acrylic acid) containing many acid groups such as carboxyl groups as the main component. By adjusting the pH to a neutral to alkaline range with an alkaline agent, a network structure is formed, thereby exerting a thickening effect. Note that the alkali-soluble poly(meth)acrylic acids (alkali-soluble poly(meth)acrylic acid thickeners) of the present invention also include alkali-swellable poly(meth)acrylic acids (alkali-swellable poly(meth)acrylic acid thickeners).

[0097] Therefore, the (meth)acrylic compound used as a thickener is an alkali-soluble thickener, that is, a thickener that solubilizes a polymer with alkali during use to increase the thickening force. Examples of such thickeners include an ASE (Alkali Soluble Emulsion) type in which no associative group (e.g., a hydrophobic group) has been introduced, and a HASE (Hydrophobically modified Alkali Soluble Emulsion) type in which an associative group (e.g., a hydrophobic group) has been introduced to increase the thickening power, with the HASE type in which an associative group has been introduced to increase the thickening power being preferred.

[0098] When a (meth)acrylic compound of an alkali-soluble thickener is used, poly(meth)acrylic acid and an alkali are used in combination. Examples of the alkali include inorganic alkalis such as sodium hydroxide, potassium hydroxide, and ammonia, and organic alkalis such as triethanolamine. By adding an alkali, poly(meth)acrylic acid exhibits a thickening effect. Furthermore, the thickener may be either a Newtonian fluid or a non-Newtonian fluid.

[0099] The content of thickener in polishing composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, based on the total mass of polishing composition.In addition, the content of thickener in polishing composition is preferably 3.0 mass% or less, more preferably 2.0 mass% or less, based on the total mass of polishing composition.When the content of thickener is within the above range, the viscosity of polishing composition is improved, and can prevent the liquid of polishing composition from dripping on surfaces other than horizontal surfaces such as the side of ships and automobile bodies.

[0100] [Emulsion Stabilizer] The polishing composition according to this embodiment may contain an emulsion stabilizer, which has the effect of increasing the compatibility between the hydrophobic dispersion medium and water and improving stability.

[0101] Examples of emulsion stabilizers include hydrophilic organic solvents other than water that are miscible with water, such as alcohol (monool) solvents such as methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-pentanol, cetyl alcohol, and stearyl alcohol; Diol solvents such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,3-propanediol, isobutylene glycol, triethylene glycol, tripropylene glycol, tetraethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,2-propanediol, 2-methyl-1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,2-hexanediol, 1,5-pentanediol, 1,6-hexanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,3-butanediol, 3-methyl-1,5-pentanediol, and 2-methyl-2,4-pentanediol; Examples of suitable solvents include triol-based solvents such as glycerin, trimethylolethane, trimethylolpropane, and 1,2,6-hexanetriol; tetraol-based solvents such as diglycerin, mesoerythritol, and pentaerythritol; ketone-based solvents or ketoalcohol-based solvents such as acetone, methyl ethyl ketone, diacetone alcohol, and Texanol (3-hydroxy-2,2,4-trimethylpentyl 2-methylpropanoate); and polyoxyalkylene glycol-based solvents such as oxyalkylene homopolymers (polymers containing only one type of oxyalkylene group), oxyalkylene copolymers (copolymers containing two or more types of oxyalkylene groups), and oxyalkylene alkyl ethers having a short-chain hydrophobic group. Examples of suitable polyoxyalkylene alkyl ethers having a short-chain hydrophobic group include polyoxyalkylene alkyl ethers having an alkyl ether containing 1 to 10 carbon atoms. The polyoxyalkylene alkyl ether preferably contains 1 to 8 carbon atoms, and more preferably contains 1 to 6 carbon atoms.

[0102] The content of emulsion stabilizer in polishing composition is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, based on the total mass of polishing composition.In addition, the content of emulsion stabilizer in polishing composition is preferably 3.0 mass% or less, more preferably 2.5 mass% or less, based on the total mass of polishing composition.When the content of emulsion stabilizer is within the above range, the stability of polishing composition can be further improved.

[0103] [Additives] The polishing composition according to this embodiment may contain additives. Examples of additives include pH adjusters, antifungal agents (preservatives), antifoaming agents, dissolved gases, reducing agents, oxidizing agents, and alkanolamines. Known additives can be used as these additives.

[0104] The polishing composition of this embodiment may contain a base or its salt as a pH adjuster. Examples of the base or its salt include amines such as aliphatic amines and aromatic amines, organic bases such as quaternary ammonium hydroxide, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, hydroxides of Group 2 elements such as magnesium hydroxide and calcium hydroxide, and ammonia.

[0105] The polishing composition of this embodiment may contain an acid or its salt as a pH adjuster. The acid may be either an inorganic acid or an organic acid. Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, hydrofluoric acid, boric acid, carbonic acid, hypophosphorous acid, phosphorous acid, and phosphoric acid. Examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, 2-methylbutyric acid, n-hexanoic acid, 3,3-dimethylbutyric acid, 2-ethylbutyric acid, 4-methylpentanoic acid, n-heptanoic acid, 2-methylhexanoic acid, n-octanoic acid, 2-ethylhexanoic acid, benzoic acid, glycolic acid, salicylic acid, glyceric acid, oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, maleic acid, phthalic acid, malic acid, tartaric acid, citric acid, lactic acid, diglycolic acid, 2-furancarboxylic acid, 2,5-furandicarboxylic acid, 3-furancarboxylic acid, 2-tetrahydrofurancarboxylic acid, methoxyacetic acid, methoxyphenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, sulfosuccinic acid, benzenesulfonic acid, toluenesulfonic acid, phenylphosphonic acid, and hydroxyethane-1,1-diphosphonic acid. Further, examples of salts include Group 1 element salts (alkali metal salts), Group 2 element salts (alkaline earth metal salts), aluminum salts, ammonium salts, amine salts, and quaternary ammonium salts. These acids or salts can be used alone or in combination. Among these, nitric acid and citric acid are preferred.

[0106] [pH of polishing composition] The polishing composition of this embodiment is not particularly limited, but the pH can be adjusted by the above-mentioned pH adjuster. In one embodiment, the pH of the polishing composition is preferably pH 4 or more and 12 or less, more preferably pH 5 or more and 11 or less, even more preferably pH 6 or more and 10 or less, and particularly preferably pH 7 or more and 10 or less.

[0107] [Method for producing polishing composition] The method for producing a polishing composition according to this embodiment includes a step of mixing abrasive grains, water, and a hydrophobic dispersion medium. By using such a production method, a polishing composition that can achieve the desired effects of the present invention can be produced. That is, the present invention also provides a method for producing a polishing composition.

[0108] In the method for producing a polishing composition according to the present embodiment, it is preferable that the abrasive grains are mixed with water to prepare an abrasive grain dispersion. Therefore, it is preferable that the method for producing a polishing composition according to the present embodiment includes a step of mixing the abrasive grains with water to obtain an abrasive grain dispersion. At this time, it is preferable that the abrasive grains are (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０ The abrasive grains are appropriately adjusted so that the flatness of the abrasive grains having a larger particle size is greater than 3.3 and less than 30. For example, when using commercially available abrasive grains, the abrasive grains can be crushed, classified (classified using a sieve, etc.), or combined with two or more types of abrasive grains; when synthesizing abrasive grains, the abrasive grains can be adjusted to have the above particle size distribution and particle shape by adjusting the abrasive grain synthesis conditions (reaction temperature, reaction time, etc.). For example, when one type of abrasive grain has the above particle size distribution and particle shape, the abrasive grain dispersion can be prepared by adding the abrasive grains to water and mixing them. Furthermore, when combining two or more types of abrasive grains, the abrasive grain dispersion can be prepared by adding two or more types of abrasive grains in a blending ratio such that the above particle size distribution and particle shape are obtained, respectively, to water and mixing them. Here, the water is prepared separately from the water added to the hydrophilic mixture described below. The abrasive grain concentration in the abrasive grain dispersion is not particularly limited and can be appropriately adjusted depending on the relationship between the water content of the polishing composition and the water used in the hydrophilic mixture described below. The abrasive dispersion may contain components such as a thickener, additives (preservatives, pH adjusters), etc. Some or all of the abrasive may be used as powder without premixing with water, i.e., without preparing the abrasive dispersion.

[0109] In the manufacturing method of the polishing composition of this embodiment, it is preferable to include the step of classifying the components contained in the polishing composition into hydrophilic components and hydrophobic components, and separately preparing a hydrophilic mixture containing hydrophilic components and a hydrophobic mixture containing hydrophobic components.Therefore, the manufacturing method of the polishing composition of this embodiment includes the step of mixing water and, if necessary, hydrophilic components such as thickeners and emulsion stabilizers to obtain a hydrophilic mixture; and the step of mixing a hydrophobic dispersion medium, surfactants, and, if necessary, hydrophobic components such as oils to obtain a hydrophobic mixture.

[0110] The method for producing a polishing composition according to this embodiment preferably includes a step of mixing a hydrophilic mixture, a hydrophobic mixture, and an abrasive dispersion to obtain a polishing composition. Here, the step of obtaining a polishing composition may include a step of emulsifying the hydrophilic mixture and the hydrophobic mixture to obtain an emulsion; and a step of mixing the emulsion and the abrasive dispersion. In the step of mixing the emulsion and the abrasive dispersion, the abrasive dispersion may be added to the emulsion, or the emulsion may be added to the abrasive dispersion. Some or all of the abrasive may be added as powder, or the hydrophilic mixture, the hydrophobic mixture, and the abrasive powder may be mixed.

[0111] As a method of mixing to obtain an abrasive dispersion, an emulsion, or a polishing composition, ultrasonic waves, a magnetic stirrer, a three-one motor, a homogenizer, etc. When mixing an abrasive dispersion, it is preferable to mix by irradiating ultrasonic waves, when mixing an emulsion, it is preferable to mix using a homogenizer, and when mixing to obtain a polishing composition, it is preferable to mix by ultrasonic waves or a three-one motor.

[0112] In each of the above steps, the temperature at which the components are mixed is not particularly limited, but is preferably 10° C. or higher and 40° C. or lower. The mixing time is not particularly limited.

[0113] [Object to be polished] The object to be polished according to the present invention is not particularly limited, but preferably includes at least one selected from the group consisting of alloy materials, resin materials, metals, semi-metals, metal oxides, metal carbides, metal nitrides, semi-metal oxides, semi-metal carbides, semi-metal nitrides, and glass materials, and may also be a composite material of these materials. In particular, resin materials used for painted surfaces of automobile bodies, ships, etc. are preferred.

[0114] Hereinafter, alloy materials, resin materials, metals, semi-metals, and materials such as oxides, carbides, and nitrides thereof, as well as glass materials will be described.

[0115] [Alloy material] An alloy material is a compound in which a metal element, which is the main component, is shared with one or more metal elements different from the main component, or non-metallic elements such as carbon, nitrogen, or silicon, and is manufactured with the aim of improving properties such as mechanical strength, chemical resistance, corrosion resistance, and heat resistance compared to pure metals.

[0116] Alloy materials are named based on the metal species that constitute their main component. Examples of alloy materials include aluminum alloys, iron alloys, titanium alloys, nickel alloys, and copper alloys. These alloy materials may be used alone or in combination. Among these, it is preferable to use at least one selected from the group consisting of aluminum alloys and iron alloys. Furthermore, alloy materials in which the Vickers hardness (HV) difference between the main metal species and the other metal species is 5 or more are preferred. Aluminum alloys are lightweight and have excellent strength, making them useful in a variety of applications, including structural materials such as building materials and containers, transportation equipment such as automobiles, ships, and aircraft, various electrical appliances, and electronic components. Titanium alloys are lightweight and highly corrosion-resistant, making them widely used in precision instruments, decorative items, tools, sporting goods, medical components, and more. Iron alloys, such as stainless steel and nickel alloys, have excellent corrosion resistance and are therefore used in a variety of applications, including structural materials, transportation equipment, tools, machinery, and cooking utensils. Copper alloys have excellent electrical conductivity, thermal conductivity, and corrosion resistance, as well as excellent workability and beautiful finishes, and are therefore widely used in decorative items, tableware, musical instruments, electrical components, etc. Furthermore, materials containing resins have recently been used for the above-mentioned applications.

[0117] The aluminum alloy contains aluminum as the main component, and preferably contains at least one metal selected from the group consisting of magnesium, silicon, copper, zinc, manganese, chromium, and iron as a metal species other than the main component. The lower limit of the content of the metal species other than the main component in the aluminum alloy is not particularly limited, but is preferably 0.1 mass% or more with respect to the entire aluminum alloy. The upper limit of the content of the metal species other than the main component in the aluminum alloy is not particularly limited, but is preferably 10 mass% or less with respect to the entire aluminum alloy.

[0118] Specific examples of aluminum alloys include Al-Cu and Al-Cu-Mg alloys with numbers in the 2000s, Al-Mn alloys with numbers in the 3000s, Al-Si alloys with numbers in the 4000s, Al-Mg alloys with numbers in the 5000s, Al-Mg-Si alloys with numbers in the 6000s, Al-Zn-Mg alloys with numbers in the 7000s, and Al-Fe-Mn alloys with numbers in the 8000s, as described in JIS H4000:2006.

[0119] The iron alloy contains iron as the main component and preferably contains at least one metal selected from the group consisting of chromium, nickel, molybdenum, and manganese as a metal species other than the main component. The lower limit of the content of the metal species other than the main component in the iron alloy is not particularly limited, but is preferably 10 mass% or more based on the total iron alloy. The upper limit of the content of the metal species other than the main component in the iron alloy is not particularly limited, but is preferably 50 mass% or less based on the total iron alloy.

[0120] The iron alloy is preferably stainless steel. Specific examples of stainless steel include, for example, SUS201, SUS303, 303Se, SUS304, SUS304L, SUS304NI, SUS305, SUS305JI, SUS309S, SUS310S, SUS316, SUS316L, SUS321, SUS347, SUS384, SUSXM7, SUS303F, SUS303C, SUS430, SUS430F, SUS434, SUS410, SUS416, SUS420J1, SUS420J2, SUS420F, SUS420C, and SUS631J1, among others, in terms of the types of symbols described in JIS G4303:2005.

[0121] Titanium alloys contain titanium as the main component and, as metal species other than the main component, for example, aluminum, iron, vanadium, etc. The content of the metal species other than the main component in the titanium alloy is, for example, 3.5 mass % or more and 30 mass % or less of the total titanium alloy. Examples of titanium alloys include types 11 to 23, 50, 60, 61, and 80 of the types described in JIS H4600:2012.

[0122] The nickel alloy contains nickel as the main component and at least one metal selected from iron, chromium, molybdenum, and cobalt as a metal species different from the main component. The content of the metal species different from the main component in the nickel alloy is, for example, 20% by mass or more and 75% by mass or less based on the total nickel alloy. Examples of nickel alloys include alloy numbers NCF600, 601, 625, 750, 800, 800H, 825, NW0276, 4400, 6002, and 6022 listed in JIS H4551:2000.

[0123] The copper alloy contains copper as the main component and at least one metal selected from iron, lead, zinc, and tin as a metal species other than the main component. The content of the metal species other than the main component in the copper alloy is, for example, 3% by mass or more and 50% by mass or less of the total copper alloy. Examples of copper alloys include alloy numbers C2100, 2200, 2300, 2400, 2600, 2680, 2720, 2801, 3560, 3561, 3710, 3713, 4250, 4430, 4621, 4640, 6140, 6161, 6280, 6301, 7060, 7150, 1401, 2051, 6711, and 6712 in accordance with JIS H3100:2006.

[0124] [Resin Material] The type of resin material is not particularly limited, and may be either a thermosetting resin or a thermoplastic resin.

[0125] Examples of thermosetting resins include epoxy resins, polyimide resins, phenolic resins, amino resins, unsaturated polyester resins, thermosetting polyurethane resins (polyurethane resins, urethane (meth)acrylic resins, etc.), melamine resins, etc.

[0126] Examples of thermoplastic resins include polystyrene resin, acrylonitrile-butadiene-styrene copolymer resin (ABS resin), (meth)acrylic resin (methacrylic and / or acrylic resin), organic acid vinyl ester resin or derivatives thereof, vinyl ether resin, halogen-containing resins such as polyvinyl chloride, polyvinylidene chloride, and polyvinylidene fluoride, olefin resins such as polyethylene and polypropylene, saturated polyester resins such as polycarbonate resin, polyethylene terephthalate, and polyethylene naphthalate, polyamide resin, thermoplastic polyurethane resin, polysulfone resin (polyethersulfone, polysulfone, etc.), polyphenylene ether resin (2,6-xylenol polymer, etc.), cellulose derivatives (cellulose esters, cellulose carbamates, cellulose ethers, etc.), silicone resin (polydimethylsiloxane, polymethylphenylsiloxane, etc.), and the like.

[0127] The above resins can be used alone or in combination of two or more. Among these resins, unsaturated polyester resins, saturated polyester resins, polycarbonate resins, and thermosetting polyurethane resins (polyurethane resins, urethane (meth)acrylic resins, etc.) are more preferred from the viewpoints of impact resistance and weather resistance.

[0128] The object to be polished containing a resin material is not particularly limited, and may be, for example, a member (resin member) formed from a resin material, or a composite material having a resin coating on the surface of a metal substrate, etc. Resins used for the coating include thermosetting polyurethane resins (polyurethane resins, urethane (meth)acrylic resins, etc.), (meth)acrylic resins, fiber reinforced plastics (FRP: Fiber Reinforced Plastics) resins, etc.

[0129] Examples of FRP resins include glass fiber reinforced plastic (GFRP) resin, carbon fiber reinforced plastic (CFRP) resin, and aramid fiber reinforced plastic (aramid fiber composite material, AFC) resin. The resin coating may be a transparent clear coating, or a colored coating, such as white, black, or other colors. The polishing composition of this embodiment can be used on a resin coating in a cured state or a semi-cured state where it is beginning to cure.

[0130] The polishing composition according to this embodiment is preferably used for resin coating films having a pencil hardness of 10B or more and 10H or less as measured by the pencil method described in JIS K 5600-5-4 (1999), and examples thereof include polyester resin coating films having a pencil hardness of 3H applied to FRP, polyurethane resin coating films or urethane (meth)acrylic resin coating films having a pencil hardness of F applied to metal substrates, and polyurethane resin coating films or urethane (meth)acrylic resin coating films having a pencil hardness of 10B applied to metal substrates. Generally, the pencil hardness of a resin coating film in a cured state is B or more, and the pencil hardness of a resin coating film in a semi-cured state is less than B.

[0131] The composite material having a resin coating film is not particularly limited, but an example thereof is a three-dimensional resin material. Applications of the three-dimensional resin material include, for example, automobile bodies, railroad vehicles, ships, aircraft, and resin components. Resin coatings coated on the surfaces of automobile bodies, railroad vehicles, ships, and aircraft have large areas and curved surfaces, and the polishing composition of this embodiment is suitable for polishing the outer surfaces of such resin coatings. Therefore, according to one embodiment, the polishing composition of this embodiment is used for polishing resins.

[0132] According to one embodiment, the polishing composition according to this embodiment is used to polish an FRP resin (FRP molded product) coated with a gel coat. That is, according to one embodiment, the polishing composition according to this embodiment is used to polish a gel coat layer formed on the FRP resin (FRP molded product). Polishing the gel coat layer can improve unevenness in the thickness of the FRP resin (FRP molded product) and unevenness in the smoothness of the gel coat surface. The thickness of the gel coat layer formed on the surface of the FRP resin (FRP molded product) is preferably 0.1 to 3 mm, more preferably 0.15 to 2 mm, and even more preferably 0.2 to 1 mm.

[0133] Gel coats are generally formed from resin compositions containing unsaturated polyester resins. A method for coating an FRP resin (FRP molded product) with a gel coat involves placing a gel coat layer on a molding die, placing a fiber reinforcement on top of the gel coat layer (which would be the inner side of the molded product), and curing the FRP resin composition to obtain a molded product in which the FRP resin is formed inside the gel coat layer. The molded product is then removed from the molding die to obtain a gel-coated FRP resin (FRP molded product). The outer surface of the removed FRP resin (FRP molded product) becomes the gel coat layer. Polishing the gel coat layer on the resulting FRP resin (FRP molded product) with the polishing composition of this embodiment improves the smoothness of the resin (FRP molded product).

[0134] Gel coats are sometimes applied to the surface of FRP resin products to repair scratches on the surface. In this case, a fiber reinforcement and a resin composition for FRP are layered over the scratch, and then a gel coat is applied on top of that. By polishing the gel coat layer on the FRP resin (FRP molded product) resulting from such scratch repair with the polishing composition of this embodiment, the smoothness of the resin (FRP molded product) is improved.

[0135] According to one embodiment, the polishing composition according to this embodiment is used for polishing a clear coating coated on an alloy or the like. That is, according to one embodiment, the polishing composition according to this embodiment is used to polish a clear coating layer formed on an alloy. Polishing the clear coating layer with the polishing composition according to this embodiment can remove waviness in the clear coating layer.

[0136] [Metals, semi-metals, and their oxides, carbides, and nitrides] Examples of metals include aluminum, iron, zirconium, copper, nickel, gold, silver, bismuth, manganese, and zinc.

[0137] Examples of semimetals include group IV semiconductors such as silicon (Si) and germanium (Ge), group II-VI compound semiconductors such as zinc selenide (ZnSe), cadmium sulfide (CdS), and zinc oxide (ZnO), group III-V compound semiconductors such as gallium arsenide (GaAs), indium phosphide (InP), and gallium nitride (GaN), group IV compound semiconductors such as silicon carbide (SiC) and silicon germanium (SiGe), and copper indium selenium (CuInSe). ２ ) and other chalcopyrite-based semiconductors.

[0138] It can also be suitably used for oxides, carbides, and nitrides of these materials.

[0139] [Glass Material] Examples of glass materials include soda lime glass, quartz glass, tempered glass, crystallized glass, aluminosilicate glass, and glassy carbon.

[0140] [Polishing Method] As described above, the polishing composition of the present embodiment is suitable for polishing an object to be polished that contains an alloy material, a resin material, a metal, a semi-metal, a metal oxide, a metal carbide, a metal nitride, a semi-metal oxide, a semi-metal carbide, a semi-metal nitride, or a glass material, as well as a composite material of these materials. Thus, according to one embodiment, the object to be polished contains at least one material selected from the group consisting of a resin material, an alloy material, and a glass material.

[0141] The polishing composition according to this embodiment is suitable for polishing an object having a curved surface (e.g., a painted surface of an automobile or the like, or a ship). Therefore, the present invention also provides a polishing method comprising a polishing step of polishing an object using the polishing composition according to this embodiment. According to this polishing method, the object to be polished is a painted surface, and the painted surface is polished with a wool buff and / or a sponge buff. According to one embodiment, the polishing step comprises supplying the polishing composition to the surface of the object to be polished and polishing the surface by contacting the polishing buff with the surface to which the polishing composition has been supplied. According to another embodiment, a polishing method is provided in which the painted surface is polished, preferably with a wool buff, using the polishing composition according to this embodiment. According to another embodiment, a polishing method is provided in which the painted surface is polished with a sponge buff using the polishing composition according to this embodiment.

[0142] A method for polishing a resin-coated surface will be described below as an example of the polishing method according to the present embodiment. The configuration of the polishing device used for polishing is not particularly limited, and general polishing devices such as a handheld polisher, a single-sided polisher, a double-sided polisher, or a lens polisher may be used, as well as the automatic polishing device shown in FIG. 1 of International Publication No. 2019 / 066014 (the polishing pad 10 in FIG. 1 corresponds to the polishing buff).

[0143] For example, the polishing method according to this embodiment may be applied when an abrasive buff is attached to the tip of a hand polisher and a polisher manually operates the hand polisher to polish a resin-coated surface. The driving means of the hand polisher is not particularly limited, but generally, single action, double action, gear action, etc. are used, and single action and double action are preferred for polishing coated members.

[0144] When polishing an object to be polished, such as an alloy material, using the polishing composition of this embodiment, the polishing can be carried out using equipment and conditions commonly used for metal polishing. In a single-side polishing apparatus, a holder called a carrier is used to hold the object to be polished (preferably a substrate-like object to be polished), and one side of the object to be polished is polished by pressing a platen with an abrasive cloth attached to one side of the object to be polished and rotating the platen while supplying a polishing composition. In a double-side polishing apparatus, a holder called a carrier is used to hold the object to be polished, and while supplying a polishing composition from above, a platen with an abrasive cloth attached to the opposite side of the object to be polished is pressed against the opposite side of the object to be polished, and the two plates are rotated in relative directions to polish both sides of the object to be polished. At this time, polishing is carried out by the physical action of friction between the polishing pad and the polishing composition and the object to be polished, and the chemical action of the polishing composition on the object to be polished.

[0145] The polishing load can be mentioned as a polishing condition in the polishing method according to the present embodiment. Generally, the higher the load, the higher the frictional force caused by the abrasive grains, and the mechanical processing force improves, resulting in an increase in the processing force and polishing rate. The lower limit of the polishing load in the polishing method according to the present embodiment is not particularly limited, but is preferably 5 g / cm. ２ It is preferable that the density is 10 g / cm or more. ２ As the polishing load increases, the mechanical processing characteristics improve, and the processing force increases. The upper limit of the polishing load is 100 kg / cm. ２ Preferably, it is 50 kg / cm or less. ２ As the polishing load decreases, surface roughness of the polished surface is more suppressed.

[0146] Further, the polishing conditions in the polishing method according to this embodiment include the linear velocity during polishing (linear polishing velocity). Generally, the linear velocity is affected by the rotation speed of the polishing pad, the rotation speed of the carrier, the size of the object to be polished, the number of objects to be polished, etc., but when the linear velocity is high, the frictional force acting on the object to be polished increases, making the object to be polished more likely to be mechanically polished. In addition, frictional heat may be generated due to friction, which may increase the chemical action of the polishing composition. The lower limit of the linear polishing velocity in the polishing method according to this embodiment is not particularly limited, but is preferably 10 m / min or more, more preferably 20 m / min or more. The upper limit of the linear polishing velocity is preferably 1000 m / min or less, more preferably 500 m / min or less. Within this range, a sufficiently high processing force can be obtained, and an appropriate frictional force can be applied to the object to be polished. That is, in this embodiment, the linear polishing velocity is preferably 10 m / min or more to 1000 m / min or less, more preferably 20 m / min or more to 500 m / min or less.

[0147] The polishing composition of this embodiment may be used in a process completed in one stage, or may be used in one or more stages of a process having multiple polishing stages. For example, when used in a process having three polishing stages, it can be used in one or more stages of the first stage (rough polishing), the second stage (medium polishing), and the third stage (finish polishing).

[0148] When using the polishing composition of this embodiment to polish an object to be polished, the polishing composition that has been used for polishing can be recovered and used again for polishing.As an example of the method for reusing the polishing composition, the polishing composition that is discharged from the polishing device can be recovered in a tank, and can be recycled and used again in the polishing device.Recycling the polishing composition is useful in that it can reduce the amount of the polishing composition that is discharged as waste liquid, thereby reducing environmental load, and it can reduce the amount of the polishing composition that is used, thereby reducing the manufacturing cost required for polishing the object to be polished.

[0149] When the polishing composition of this embodiment is recycled, a part or all of the abrasive grains and other additives consumed or lost during polishing can be added as a composition adjuster during the recycling process.In this case, the composition adjuster may be a mixture of abrasive grains and some or all of the other additives at any mixing ratio.By adding additional composition adjuster, the polishing composition is adjusted to a composition suitable for reuse, and polishing is maintained favorably.The concentration of the abrasive grains and other additives contained in the composition adjuster is arbitrary and is not particularly limited, but it is preferable to adjust it appropriately depending on the size of the circulation tank and the polishing conditions.

[0150] The polishing composition according to the present invention may be a one-component type or a multi-component type such as a two-component type. The polishing composition according to the present invention may also be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more, with a diluent such as water or oil.

[0151] The polishing buff used in the polishing method using the polishing composition of this embodiment may be made of a material such as wool type, polyurethane type, foamed polyurethane type, nonwoven fabric type, or suede type.

[0152] Although the embodiments of the present invention have been described in detail, it is clear that this is for illustrative and exemplary purposes only and not for limitation, and that the scope of the present invention should be interpreted by the appended claims.

[0153] The present invention encompasses the following aspects and configurations.

[0154] [1] Abrasive grains, water, and a hydrophobic dispersion medium are included, and in the volume-based particle size distribution of the abrasive grains, the particle diameters at which the cumulative volume from the large particle side is 10 volume %, 50 volume %, and 90 volume %, respectively, are defined as D １０ , D ５０ , and D ９０ When the particle size distribution width (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０A polishing composition, wherein the flatness of the abrasive grains having a larger particle size is more than 3.3 and less than 30.

[0155] [2] D of the abrasive grains １０ and D ９０ The ratio (D １０ / D ９０ ) is 3.6 or more and 50 or less.

[0156] [3] Average secondary particle diameter D of the abrasive grains ５０ The polishing composition according to the above [1] or [2], wherein the particle size is 0.05 μm or more and 15 μm or less.

[0157] [4] The D １０ The polishing composition according to any one of the above [1] to [3], wherein the circularity of the abrasive grains having a larger particle size exceeds 0.6.

[0158] [5] The polishing composition according to any one of [1] to [4] above, wherein the content of the abrasive grains is 5% by mass or more and 50% by mass or less relative to the total mass of the polishing composition.

[0159] [6] The polishing composition according to any one of [1] to [5] above, wherein the water content is 52 mass % or less based on the total mass of the polishing composition.

[0160] [7] The polishing composition according to any one of [1] to [6] above, wherein the abrasive grains have a water absorption of 20 mL / 100 g or more.

[0161] [8] The polishing composition according to any one of [1] to [7] above, wherein the abrasive grains contain aluminum oxide.

[0162] [9] The polishing composition according to the above [8], wherein the alpha conversion rate of the aluminum oxide is 50% or more and 100% or less.

[0163]

[10] The polishing composition according to any one of [1] to [9] above, wherein the hydrophobic dispersion medium contains at least one selected from the group consisting of normal paraffin hydrocarbons, isoparaffin hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons, and has a flash point of 30°C or higher and 140°C or lower.

[0164]

[11] The polishing composition according to any one of the above [1] to

[10] , wherein the hydrophobic dispersion medium has a vapor pressure at 20°C of 0.0001 kPa or more and 2 kPa or less.

[0165]

[12] The polishing composition according to any one of the above [1] to

[11] , wherein the flash point of the hydrophobic dispersion medium is higher than 100°C and not higher than 140°C.

[0166]

[13] The polishing composition according to any one of the above [1] to

[11] , wherein the hydrophobic dispersion medium has a flash point of 60°C or higher and 100°C or lower.

[0167]

[14] The particle size distribution width (D １０ -D ９０ ) / D ５０

[14] The polishing composition according to any one of [1] to

[13] above, wherein the value of [amount of polishing] is 1.55 or more and 3.0 or less.

[0168]

[15] The particle size distribution width (D １０ -D ９０ ) / D ５０

[14] The polishing composition according to any one of [1] to

[13] above, wherein the polishing composition has a viscosity of more than 3.0 and not more than 10.0.

[0169]

[16] The polishing composition according to any one of [1] to

[15] above, further comprising a surfactant.

[0170]

[17] The polishing composition according to any one of [1] to

[16] above, which is used for polishing resins.

[0171]

[18] A polishing method comprising a step of polishing an object to be polished with the polishing composition according to any one of [1] to

[17] above.

[0172]

[19] The polishing method according to

[18] above, wherein the object to be polished comprises at least one material selected from the group consisting of a resin material, an alloy material, and a glass material.

[0173]

[20] The polishing method according to

[18] or

[19] above, wherein in the step of polishing the object to be polished, the polishing composition is supplied to the surface of the object to be polished, and the surface to which the polishing composition has been supplied is brought into contact with a polishing buff to polish it.

[0174] The present invention will be described in more detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited to the following examples. Unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass", respectively. In the following examples, unless otherwise specified, the operations were carried out under the conditions of room temperature (20°C to 25°C) and relative humidity of 30% RH to 50% RH.

[0175] <<Regarding Each Component>> The abrasive grains, hydrophobic dispersion medium, and surfactants used in the following examples and comparative examples were as follows.

[0176] [Abrasive grains] The following abrasive grains were used: Abrasive grain a: aluminum oxide (alpha conversion rate 96%, D ５０ = 2.9 μm, SA (specific surface area) = 8.6 m ２ / g, water dispersion (water absorption cannot be measured)) Abrasive grain b: aluminum oxide (product name: PWA12, manufactured by Fujimi Inc.) (plate-shaped grain, alpha conversion rate 79%, D ５０ =9.2μm, SA=1.0m ２ / g, water absorption 22 mL / 100 g) Abrasive grain c: aluminum oxide (product name: PWA15, manufactured by Fujimi Incorporated Co., Ltd.) (plate-shaped grain, alpha conversion rate 79%, D ５０ =11.8μm, SA=0.6m ２ / g, water absorption 26 mL / 100 g) Abrasive grain d: aluminum oxide (product name: PWA9, manufactured by Fujimi Incorporated) (plate-shaped grain, alpha conversion rate 79%, D ５０ =8.3μm, SA=0.9m ２ / g, water absorption 19 mL / 100 g) Abrasive grain e: aluminum oxide (product name: WA#1500, manufactured by Fujimi Incorporated Co., Ltd.) (alpha conversion rate 100%, D ５０ =10.5μm, SA=0.9m ２ / g, water absorption 30 mL / 100 g) Abrasive grain f: aluminum oxide (product name: PWA35, manufactured by Fujimi Incorporated Co., Ltd.) (plate-shaped grain, alpha conversion rate 79%, D ５０ =25.5μm, SA=0.2m ２ / g, water absorption 33 mL / 100 g) Abrasive grain g: aluminum oxide (product name: PWA30, manufactured by Fujimi Incorporated Co., Ltd.) (plate-shaped particles, alpha conversion rate 79%, D ５０ =20.8μm, SA=0.2m ２ / g, water absorption 32mL / 100g) Abrasive grain h: aluminum oxide (alpha conversion rate 61%, D ５０ =3.9μm, SA=15.6m ２ / g, water absorption 50mL / 100g) Abrasive grain i: silicon dioxide (D ５０ =7.0μm, SA=16.7m ２ / g, water absorption 270mL / 100g).

[0177] The alpha phase ratio of aluminum oxide was measured as follows: An X-ray analyzer (Ultima-IV, manufactured by Rigaku Corporation) was used, and commercially available alpha alumina particles (alpha phase ratio 100%), which had been fired at a sufficiently high temperature and had undergone sufficient alpha phase transformation, were used as the reference material. The integrated intensities of the (113) plane diffraction line were measured by X-ray diffraction for the reference material and the aluminum oxide particles (abrasive grains) to be measured, and the alpha phase ratio of the aluminum oxide (abrasive grains) was calculated from the ratio of the integrated intensity of the (113) plane diffraction line of the aluminum oxide particles (abrasive grains) to that of the reference material.

[0178] [Aqueous Abrasive Dispersions] Examples 1 to 8 and Comparative Examples 1 to 4 The above-described abrasive grains a to f were combined to prepare aqueous abrasive dispersions in advance for use in preparing the polishing compositions of Examples 1 to 8 and Comparative Examples 1 to 4. The abrasive grain concentrations in the polishing compositions finally obtained and the specific surface areas of the abrasive grains after mixing (specific surface area of ​​the abrasive grains as a whole) are shown below: Example 1: Abrasive grain concentration 20 mass % (SA of the abrasive grains as a whole = 6.7 m ２ / g) Example 2: Abrasive grain concentration 22 mass % (SA of the entire abrasive grains = 6.2 m ２ / g) Example 3: Abrasive grain concentration 22 mass % (SA of the entire abrasive grains = 4.8 m ２ / g) Example 4: Abrasive grain concentration 15 mass % (SA of the entire abrasive grains = 5.8 m ２ / g) Example 5: Abrasive grain concentration 30 mass % (SA of the entire abrasive grains = 5.8 m ２ / g) Example 6: Abrasive grain concentration 22 mass % (SA of the entire abrasive grains = 6.1 m ２ / g) Example 7: Abrasive grain concentration 25 mass % (SA of the entire abrasive grains = 5.9 m ２ / g) Example 8: Abrasive grain concentration 25 mass % (SA of the entire abrasive grains = 5.6 m ２ / g) Comparative Example 1: Abrasive grain concentration 15 mass % (SA of the entire abrasive grains = 8.6 m ２ / g) Comparative Example 2: Abrasive grain concentration 22 mass% (SA of the entire abrasive grains = 1.0 m ２ / g) Comparative Example 3: Abrasive grain concentration 22 mass% (SA of the entire abrasive grains = 6.2 m ２ / g) Comparative Example 4: Abrasive grain concentration 22 mass% (SA of the entire abrasive grains = 6.2 m ２ / g).

[0179] [Aqueous Abrasive Dispersions] Examples 9 to 11 and Comparative Example 5 The above-described abrasive grains a to i were combined to prepare aqueous abrasive dispersions in advance for use in preparing the polishing compositions of Examples 9 to 11 and Comparative Example 5. The polishing compositions (aqueous abrasive dispersions) of Examples 9 to 11 were prepared to contain either abrasive grain h or abrasive grain i. The abrasive grain concentrations in the polishing compositions finally obtained are shown below: Example 9: Abrasive grain concentration 35 mass % (SA of the abrasive grains as a whole = 8.4 m ２ / g) Example 10: Abrasive grain concentration 30 mass % (SA of the entire abrasive grains = 9.0 m ２ / g) Example 11: Abrasive grain concentration 24 mass% (SA of the entire abrasive grains = 7.7 m ２ / g) Comparative Example 5: Abrasive grain concentration 15 mass % (SA of the entire abrasive grains = 8.6 m ２ / g).

[0180] [Hydrophobic Dispersion Medium] The following hydrophobic dispersion media were used: Hydrophobic dispersion medium a: naphthenic hydrocarbon derived from mineral oil (flash point: 114°C, vapor pressure at 20°C: 0.001 kPa); Hydrophobic dispersion medium b: naphthenic hydrocarbon derived from mineral oil (flash point: 75°C, vapor pressure at 20°C: 0.01 kPa).

[0181] [Surfactant] A polyoxyalkylene alkyl ether having a long chain length hydrophobic group and an HLB of 13.3 was used as the surfactant.

[0182] Preparation of Polishing Compositions of Examples and Comparative Examples A hydrophobic mixture was prepared by adding 1.6% by mass of a surfactant to 16% by mass of a hydrophobic dispersion medium. Next, 1.1% by mass of an alkali-soluble polyacrylic acid polymer (thickener) and 2.0% by mass of glycerin (emulsion stabilizer) were mixed with water to prepare a hydrophilic mixture. The hydrophilic mixture was added to the hydrophobic mixture and stirred at room temperature (25°C), after which the above-mentioned aqueous abrasive dispersion was further added. The resulting dispersion was adjusted to pH 9.0 by adding sodium hydroxide as an alkali and a preservative to prepare the polishing compositions of Examples 1 to 11 and Comparative Examples 1 to 5, which were O / W emulsions. In Examples 1 to 6 and Comparative Examples 1 to 5, the polishing compositions were prepared using hydrophobic dispersion medium A, and in Examples 7 to 11, the polishing compositions were prepared using hydrophobic dispersion medium B.

[0183] The water content (charge amount) in the polishing composition in Examples 1 to 7 and the net water content in the polishing composition taking into account the water absorption of the abrasive grains were as follows: The water content (charge amount) in the polishing composition in Examples 8 to 11 and the net water content in the polishing composition taking into account the water absorption of the abrasive grains are shown in Table 2. Example 1: Water content in the polishing composition (charge amount): 58% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 57% by mass; Example 2: Water content in the polishing composition (charge amount): 56% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 55% by mass; Example 3: Water content in the polishing composition (charge amount): 56% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 54% by mass; Example 4: Water content in the polishing composition (charge amount): 63% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 62% by mass; Example 5: Water content in the polishing composition (charge amount): 48% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 46% by mass; Example 6: Water content in the polishing composition (charge amount): 53% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 51% by mass; Example 7: Water content in the polishing composition (charge amount): 53% by mass, net water content in the polishing composition taking into account the water absorption of the abrasive grains: 51% by mass.

[0184] <<Method for Evaluating Physical Properties of Abrasive Grains>> The physical properties of the abrasive grains were evaluated according to the following methods. The evaluation results are shown in Table 1.

[0185] [Measurement of particle size distribution of abrasive grains] The particle size distribution of the abrasive grains was measured using a "Multisizer 4e" (pore electrical resistance method) manufactured by Beckman Coulter, Inc. In measuring the particle size distribution of abrasive grains a to f, the aperture diameter was set to 50 μm, the aperture diameter of abrasive grains g and i was set to 100 μm, and the aperture diameter of abrasive grain h was set to 50 μm. The particle diameters of abrasive grains a to i were measured, and the D of the particle size distribution was calculated. ５０ The value of the particle diameter D ５０In the measurement of abrasive grains in the polishing compositions of Examples 1 to 7 and Comparative Examples 1 to 4, the aperture diameter was 50 μm. In the measurement of abrasive grains in the polishing compositions of Examples 8 to 11 and Comparative Example 5, an appropriate aperture diameter of 50 μm or 200 μm was used. In the polishing compositions of Examples 1 to 11 and Comparative Examples 1 to 5, the particle diameter of each abrasive grain to be mixed was measured, and the particle size distribution of the mixed abrasive grains was synthesized from the calculated values ​​using the weight ratio, and the D of the particle size distribution was calculated. １０ , D ５０ , D ９０ The value of the particle diameter D １０ , D ５０ , D ９０ It was decided.

[0186] [SEM Measurement] Images of the abrasive dispersion were observed using a scanning electron microscope SU8000 (manufactured by Hitachi High-Technologies Corporation) according to the following procedure.

[0187] The aqueous abrasive dispersions used in Examples 1 to 11 and Comparative Examples 1 to 5 were dispersed in ethanol, dried, and placed in a scanning electron microscope (SEM). The SEM images were irradiated with an electron beam at 10 kV, and several observation fields were photographed at magnifications of 500 to 200,000. The photographed SEM images were analyzed using image analysis software (WinRoof2021) (manufactured by Mountec Co., Ltd.) according to the following method: １０ Larger particles" and "D １０ The flatness and circularity of the "larger particles" were calculated.

[0188] [D １０ Method for selecting larger particles] SEM images of 100 or more particles were taken using an SEM, and the images were analyzed to determine the projected area equivalent circle diameter (the diameter of a circle having the same area as the projected area of ​​the particle). The projected area equivalent circle diameter of each particle was calculated, and this value was used as the equivalent circle diameter d Ｐ The equivalent circle diameter d Ｐ The particles used in the calculation are all particles in the captured SEM image. The circle-equivalent diameter d obtained by the SEM image analysis is Ｐ is regarded as the same value as the particle diameter obtained by measurement using the abrasive grain size distribution measuring device Multisizer 4e, and D１０ Larger circle equivalent diameter d Ｐ Particles having "D １０ Larger particles."

[0189] [Measurement of Flatness] The flatness was measured by measuring the "D １０ The larger particles were calculated by image analysis. １０ The major axis l (Feret horizontal diameter), minor axis b (Feret vertical diameter), and thickness t of particles corresponding to "larger particles" were measured. Each particle in the SEM image was visually observed, and when the particle was considered as a rectangular parallelepiped, the longest side of the three sides was taken as the major axis l, the next longest side as the minor axis b, and the shortest side as the thickness t. Using the obtained major axis l (Feret horizontal diameter) and thickness t, the flatness of each particle was calculated as (each) flatness using the following formula, and the average value was taken as the flatness: Flatness = l / t (l = major axis, t = thickness).

[0190] [Measurement of Circularity] The circularity was measured by measuring the circularity in an SEM image. １０ The larger particles were calculated by image analysis. １０ The area S and perimeter L of the particle corresponding to the "larger particle" Ｃ was determined, and the circularity of each particle was calculated as the (each) circularity using the following formula, and the average value was taken as the circularity: Circularity=4πS / L Ｃ ２ (S = area of ​​circle, L Ｃ = perimeter).

[0191] [Measurement of Specific Surface Area (SA)] The specific surface area of ​​the abrasive grains was measured by the BET method using a "Flow Sorb II 2300" manufactured by Micromeritics.

[0192] [Measurement of Water Absorption] The water absorption of the abrasive grains (in powder form) was measured in accordance with JIS K 5101-13-1:2004, using water instead of refined linseed oil.

[0193] <Evaluation of Polishing Performance A> For the polishing compositions of Examples 1 to 8 and Comparative Examples 1 to 4 obtained, the polishing performance A was evaluated by the following procedures: evaluation of processing power (scratch removal time) and evaluation of gloss.

[0194] [Evaluation of Processing Power (Scratch Removal Time)] Polishing was performed under the following polishing conditions using the polishing compositions of Examples 1 to 8 and Comparative Examples 1 to 4, and the processing power (scratch removal time) was evaluated according to the following method. As described above, the shorter the scratch removal time required to remove (eliminate) scratches, the better the processing power.

[0195] Polishing conditions: Polishing object: Material having a clear coating (pencil hardness 3H) applied with a gel coat on the surface of FRP Polishing machine: Sander Polisher 9237C (manufactured by Makita Corporation) Buff: Wool pad A-25498 (manufactured by Makita Corporation) Pressing load: Approximately 4 kg / 254 cm ２ = 16 g / cm ２ Polisher rotation speed: 1,200 rpm Amount of polishing composition supplied: 10 mL / cycle Polishing time: 3 minutes / cycle Polishing area: 650 x 480 mm Polishing time: The time required to dry-sand the clear coating film using #800 paper until removal was confirmed visually.

[0196] [Evaluation of Gloss] The state of the finished surface of the polished object was evaluated by measuring the gloss. The higher the gloss, the better the state of the finished surface. The gloss evaluation device and measurement conditions are as follows. When the scratch removal time is the same in the processing power evaluation, the higher the gloss, the better.

[0197] Measurement conditions: Evaluation device: gloss meter (GM-268Plus) manufactured by Konica Minolta, Inc. Evaluation conditions: measurement angle 20°.

[0198] <Evaluation Results> Table 1 shows the evaluation results of the processing ability (scratch removal time) and glossiness of the polishing compositions of Examples 1 to 8 and Comparative Examples 1 to 4.

[0199] <Evaluation of Polishing Performance B> For the polishing compositions of Examples 8 to 11 and Comparative Example 5 obtained, as polishing performance B, evaluation of processing power (scratch removal time) and evaluation of waviness removal ability were carried out according to the following procedures.

[0200] [Evaluation of Processing Power (Scratch Removal Time)] Polishing was performed under the following polishing conditions using the polishing compositions of Examples 8 to 11 and Comparative Example 5, and the processing power (scratch removal time) was evaluated according to the following method. As described above, the shorter the scratch removal time required to remove (eliminate) scratches, the better the processing power.

[0201] Polishing conditions: Polishing object: (1) A clear coating film (pencil hardness 10B) on the surface of a steel plate coated with RR310 manufactured by Kansai Paint and dried at 60°C for 5 hours; (2) A clear coating film (pencil hardness 5B) on the surface of a steel plate coated with Multi Diamond Clear Q3 manufactured by Kansai Paint and dried at 60°C for 5 hours. Polishing machine: PE-201 (manufactured by Ryobi Co., Ltd.) Buff: Wool buff (New Cross Wool CHIDORI manufactured by Sankyo Rikagaku Co., Ltd.) Pressing load: Approximately 4 kg / 227 cm ２ = 17.6 g / cm ２ Polisher rotation speed: 1,050 rpm Amount of polishing composition supplied: 0.4 mL / cycle Polishing time: 30 seconds / cycle Polishing area: 300 x 400 mm Polishing time: The time required to dry-sand the clear coating film using #1500 paper until removal was confirmed visually.

[0202] [Evaluation of waviness removal property] The waviness state of the clear surface of the polished object was evaluated by measuring Wc (wavelength range: 1-3 mm) measured by wave-scan dual. The lower the Wc value, the less waviness there was on the clear surface. The evaluation of waviness removal property was calculated from (Wc (initial value) - Wc (after polishing: 120 seconds)) / 120 seconds. It can be said that the higher the value calculated from this formula, the better the waviness removal property.

[0203] Evaluation conditions: Evaluation device: wave-scan dual (manufactured by BYK Instruments) Measurement length: 10 cm.

[0204] <Evaluation Results> Table 2 shows the evaluation results of the processing ability (scratch removal time) and glossiness of the polishing compositions of Examples 8 to 11 and Comparative Example 5.

[0205]

[0206]

[0207] As shown in Table 1, when the polishing compositions of Examples 1 to 8 were used, the scratch removal time was shortened, and there were no problems with respect to scratches due to the gloss level, and it was found that the polishing compositions of Examples 1 to 8 had excellent processing power.

[0208] As shown in Table 2, when the polishing compositions of Examples 8 to 11 were used, the scratch removal time was shortened and the waviness removal ability was also excellent, indicating that the polishing compositions of Examples 8 to 11 have excellent processing power.

[0209] This shows that a polishing composition containing abrasive grains having a specific particle size distribution and shape improves processing power.

[0210] This application is based on Japanese Patent Application No. 2024-130625 filed on August 7, 2024 and Japanese Patent Application No. 2024-195807 filed on November 8, 2024, the disclosures of which are incorporated herein by reference in their entirety.

Claims

1. Abrasive grains, water, and a hydrophobic dispersion medium are included, and in the particle size distribution based on volume of the abrasive grains, the particle diameters at which the cumulative volume from the large particle side is 10 volume %, 50 volume %, and 90 volume %, respectively, are defined as D １０ , D ５０ , and D ９０ When the particle size distribution width (D １０ -D ９０ ) / D ５０ is 1.55 or more and 10.0 or less, and D １０ A polishing composition, wherein the flatness of the abrasive grains having a larger particle size is more than 3.3 and less than 30.

2. D of the abrasive grains １０ and D ９０ The ratio (D １０ / D ９０ 2. The polishing composition according to claim 1, wherein the value of (a) is 3.6 or more and 50 or less.

3. Average secondary particle diameter D of the abrasive grains ５０ The polishing composition according to claim 1 or 2, wherein the particle size is 0.05 μm or more and 15 μm or less.

4. The above D １０ 3. The polishing composition according to claim 1, wherein the abrasive grains having a larger particle size have a circularity of more than 0.

6.

5. A polishing composition according to claim 1 or 2, wherein the content of the abrasive grains is 5% by mass or more and 50% by mass or less relative to the total mass of the polishing composition.

6. The polishing composition according to claim 1 or 2, wherein the water content is 52 mass % or less based on the total mass of the polishing composition.

7. The polishing composition according to claim 1 or 2, wherein the abrasive grains contain abrasive grains having a water absorption capacity of 20 mL / 100 g or more.

8. The polishing composition according to claim 1 or 2, wherein the abrasive grains contain aluminum oxide.

9. The polishing composition according to claim 8, wherein the alpha conversion rate of the aluminum oxide is 50% or more and 100% or less.

10. The polishing composition according to claim 1 or 2, wherein the hydrophobic dispersion medium contains at least one selected from the group consisting of normal paraffin hydrocarbons, isoparaffin hydrocarbons, naphthenic hydrocarbons, and terpene hydrocarbons, and has a flash point of 30°C or higher and 140°C or lower.

11. The polishing composition according to claim 10, wherein the hydrophobic dispersion medium has a vapor pressure at 20°C of 0.0001 kPa or more and 2 kPa or less.

12. The polishing composition according to claim 1 or 2, wherein the hydrophobic dispersion medium has a flash point of more than 100°C and not more than 140°C.

13. The polishing composition according to claim 1 or 2, wherein the hydrophobic dispersion medium has a flash point of 60°C or higher and 100°C or lower.

14. The particle size distribution width (D １０ -D ９０ ) / D ５０ The polishing composition according to claim 1 or 2, wherein the polishing coefficient is 1.55 or more and 3.0 or less.

15. The particle size distribution width (D １０ -D ９０ ) / D ５０ The polishing composition according to claim 1 or 2, wherein the polishing coefficient of friction coefficient is more than 3.0 and 10.0 or less.

16. The polishing composition according to claim 1 or 2, further comprising a surfactant.

17. The polishing composition according to claim 1 or 2, which is used for polishing resins.

18. A polishing method comprising a step of polishing an object to be polished using the polishing composition according to claim 1 or 2.

19. The polishing method according to claim 18, wherein the object to be polished includes at least one material selected from the group consisting of a resin material, an alloy material, and a glass material.

20. The polishing method according to claim 18, wherein in the step of polishing the object to be polished, the polishing composition is supplied to the surface of the object to be polished, and the surface to which the polishing composition has been supplied is polished by contacting a polishing buff.

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