WO2017187749A1 - Polishing composition - Google Patents

Abstract

[Problem] To provide a means for improving the dispersibility of abrasive grains while maintaining the polishing performance, and to provide a means for improving the redispersibility of abrasive grains while maintaining the polishing performance. [Solution] A polishing composition which comprises abrasive grains, a phyllosilicate compound, and a dispersion medium.

Description

Polishing composition

The present invention relates to a polishing composition.

An alloy is a common body in which one kind of metal element and one or more kinds of metal elements and non-metal elements such as carbon, nitrogen and silicon are shared with one kind of metal element. It is manufactured for the purpose of improving properties such as heat resistance, corrosion resistance and heat resistance. Among them, aluminum alloys are lightweight and have excellent strength, so they are used for various applications such as structural materials such as building materials and containers, transportation equipment such as automobiles, ships and aircraft, as well as various electrical appliances and electronic parts. It has been. In addition, titanium alloys are widely used in precision instruments, ornaments, tools, sports equipment, medical parts and the like because they are lightweight and have excellent corrosion resistance. In addition, stainless steel and nickel alloys, which are iron-based alloys, have excellent corrosion resistance, and thus are used in various applications such as tools, machinery, and cooking utensils in addition to structural materials and transportation equipment. Copper alloys are not only excellent in electrical conductivity, thermal conductivity, and corrosion resistance, but also in processability, and because of their beautiful finish, they are widely used in decorative items, tableware, musical instruments and parts of electrical materials. ing. Furthermore, recently, a material containing a resin has been used for the above-mentioned purposes.

Polishing using a polishing composition is mainly performed on the surface of an alloy or resin as described above, and further, a surface of a material such as a metal, a semimetal, or an oxide thereof, mainly for smoothing.

For example, Patent Document 1 discloses an abrasive slurry in which abrasive grains having an average particle diameter of 0.05 to 1 μm are dispersed in an aqueous medium of 0.1 to 10% by weight, and the particle diameter in the abrasive slurry is 5 μm. An abrasive slurry in which the content of the abrasive grains is 50 ppm or less is disclosed. Patent Document 2 discloses a polishing composition containing water, a polishing material, a polishing accelerator, and at least one of hydroxypropylcellulose and hydroxyalkylalkylcellulose.

JP 2000-15560 A Special table 2003-510446 gazette

However, the polishing compositions described in Patent Documents 1 and 2 have poor abrasive dispersibility, so that the polishing performance is not stable, and pipes and slurries are supplied during the production and use of the polishing composition. There was a problem that the abrasive grains settled in the tube and closed the piping. Furthermore, there was a problem that the redispersibility of the abrasive grains after long-term storage was poor.

The present invention has been made in view of the above problems, and an object thereof is to provide means for improving the dispersibility of abrasive grains while maintaining the polishing performance.

Another object of the present invention is to provide means for improving the redispersibility of abrasive grains while maintaining the polishing performance.

In order to solve the above problems, the present inventor has conducted earnest research. As a result, it has been found that the above problem can be solved by using a polishing composition containing abrasive grains, a layered silicate compound, and a dispersion medium. And based on the said knowledge, it came to complete this invention.

According to the present invention, there is provided means for improving the dispersibility of abrasive grains while maintaining the polishing performance. The present invention also provides means for improving the redispersibility of abrasive grains while maintaining the polishing performance.

The present invention is a polishing composition containing abrasive grains, a layered silicate compound, and a dispersion medium. The polishing composition of the present invention having such a configuration can improve the dispersibility of abrasive grains while maintaining polishing performance such as a high polishing rate and a reduction in surface roughness of an object to be polished. In addition, the polishing composition of the present invention having the above-described configuration can improve the redispersibility of abrasive grains while maintaining polishing performance such as a high polishing rate and a reduction in surface roughness of an object to be polished.

[Polishing object]
The polishing object according to the present invention is not particularly limited, but preferably contains at least one selected from the group consisting of alloy materials and resin materials.

Hereinafter, the alloy material and the resin material will be described.

[Alloy materials]
The alloy material contains a metal species as a main component and a metal species different from the main component.

Alloy materials are named based on the metal species as the main component. Examples of the alloy material include an aluminum alloy, an iron alloy, a titanium alloy, a nickel alloy, and a copper alloy. These alloy materials may be applied singly or in combination of two or more. Among these, it is preferable to include at least one selected from the group consisting of aluminum alloys and iron alloys.

The aluminum alloy contains aluminum as a main component, and preferably contains at least one selected from the group consisting of magnesium, silicon, copper, zinc, manganese, chromium, and iron as a metal species different from the main component. The lower limit of the content of the metal species different from the main component in the aluminum alloy is not particularly limited, but is preferably 0.1% by mass or more based on the entire aluminum alloy. Moreover, the upper limit of the content of the metal species different from the main component in the aluminum alloy is not particularly limited, but is preferably 10% by mass or less with respect to the entire aluminum alloy. According to a preferred embodiment of the present invention, the aluminum alloy contains at least one metal element selected from the group consisting of magnesium, silicon, copper, zinc, manganese, chromium, and iron over the entire aluminum alloy. On the other hand, it is an alloy containing 0.1% by mass or more.

Specific examples of the aluminum alloy include, for example, Al-Cu-based and Al-Cu-Mg-based alloy numbers 2000 series, Al-Mn-based alloy numbers 3000 series, as described in JIS H4000: 2006, Al -Si alloy number 4000 series, Al-Mg alloy number 5000 series, Al-Mg-Si alloy number 6000 series, Al-Zn-Mg alloy number 7000 series, Al-Fe-Mn series Alloy number 8000 series etc. are mentioned.

The iron alloy contains iron as a main component and preferably contains at least one selected from the group consisting of chromium, nickel, molybdenum, and manganese as a metal species different from the main component. The lower limit of the content of the metal species different from the main component in the iron alloy is not particularly limited, but is preferably 10% by mass or more based on the entire iron alloy. Moreover, the upper limit of the content of the metal species different from the main component in the iron alloy is not particularly limited, but is preferably 50% by mass or less based on the entire iron alloy. Therefore, according to a preferred embodiment of the present invention, the iron alloy contains at least one metal element selected from the group consisting of chromium, nickel, molybdenum, and manganese in an amount of 10% by mass or more based on the entire iron alloy. It is an alloy containing.

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, and SUS321 in the symbols of the type described in JIS G4303: 2005. SUS347, SUS384, SUSXM7, SUS303F, SUS303C, SUS430, SUS430F, SUS434, SUS410, SUS416, SUS420J1, SUS420J2, SUS420F, SUS420C, SUS631J1, and the like.

The titanium alloy contains titanium as a main component and contains, for example, aluminum, iron, vanadium, and the like as metal species different from the main component. Content of the metal seed | species different from the main component in a titanium alloy is 3.5 to 30 mass% with respect to the whole titanium alloy, for example. Examples of the titanium alloy include those of 11 to 23 types, 50 types, 60 types, 61 types, and 80 types in the types described in JIS H4600: 2012.

The nickel alloy contains nickel as a main component and contains at least one 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 to 75% by mass with respect to the entire nickel alloy. Examples of the nickel alloy include NCF600, 601, 625, 750, 800, 800H, 825, NW0276, 4400, 6002, 6022 and the like in the alloy number described in JIS H4551: 2000.

The copper alloy contains copper as a main component and contains at least one selected from, for example, iron, lead, zinc, and tin as a metal species different from the main component. Content of the metal seed | species different from the main component in a copper alloy is 3 to 50 mass% with respect to the whole copper alloy, for example. As a copper alloy, for example, the alloy number described in JIS H3100: 2006 is 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, 6712 and the like.

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

Examples of thermosetting resins include, for example, epoxy resins, polyimide resins, phenol resins, amino resins, unsaturated polyester resins, thermosetting polyurethane resins, and the like.

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

The above resins can be used alone or in combination of two or more. Among these resins, a thermoplastic resin is preferable from the viewpoint of impact resistance and weather resistance, and a polycarbonate resin is more preferable.

The polishing object including the resin material may be, for example, in the form of a member (resin member) formed from the resin material, or in the form of a composite material having a resin coating on the surface of a metal substrate or the like. There is no particular limitation. Examples of the resin used for the coating film include thermosetting polyurethane resins and (meth) acrylic resins. The resin coating film may be a transparent clear coating film.

Next, the configuration of the polishing composition of the present invention will be described in detail.

[Abrasive grain]
The polishing composition of the present invention contains abrasive grains. The abrasive grains have an action of mechanically polishing the object to be polished.

Specific examples of the abrasive grains used in the present invention include metal oxides such as aluminum oxide (alumina), silicon oxide (silica), cerium oxide (ceria), zirconium oxide, titanium oxide (titania), and manganese oxide. Metal carbides such as silicon carbide and titanium carbide, metal nitrides such as silicon nitride and titanium nitride, and metal borides such as titanium boride and tungsten boride. These abrasive grains may be used alone or in combination of two or more. The abrasive grains may be commercially available products or synthetic products.

Among these abrasive grains, at least one selected from the group consisting of metal oxides and metal carbides is preferable from the viewpoint that those having various particle diameters can be easily obtained and an excellent polishing rate can be obtained. Aluminum or silicon carbide is more preferred. Therefore, among these, it is more preferable that it is at least one of aluminum oxide and silicon carbide.

The lower limit of the volume average particle diameter of the abrasive grains is preferably 2.0 μm or more, more preferably 2.5 μm or more, further preferably 3.0 μm or more, and particularly preferably 3.5 μm or more. . As the volume average particle diameter of the abrasive grains increases, the polishing rate of the object to be polished improves. Further, the upper limit of the volume average particle diameter of the abrasive grains is preferably 25.0 μm or less, more preferably 15.0 μm or less, further preferably 9.5 μm or less, and 9.0 μm or less. Particularly preferred. As the volume average particle diameter of the abrasive grains decreases, it becomes easier to obtain a surface with low defects and low roughness. From the above, the volume average particle diameter of the abrasive grains is more preferably 3.0 μm or more and 9.5 μm or less, and particularly preferably 3.5 μm or more and 9.0 μm or less. Moreover, according to the preferable form of this invention, they are 2.0 micrometers or more and 9.5 micrometers or less. If the volume average particle diameter is less than 2.0 μm, the processing force required for the removal in the previous process may not be obtained, and if it exceeds 25 μm, the load on the subsequent process may be increased. Therefore, if it is the said range, the processing force required for the removal of a front process will be obtained, and the effect of this invention will be acquired, without increasing the load to a back process, and it is especially 9.5 micrometers or less. The effect can be obtained.

As a method of mirroring a metal material, a rough polishing process for removing high-quality scratches (scratches) caused by mechanical grinding of the metal material at a high speed or improving smoothness is generally performed. A method of sequentially performing a mirror polishing step and the like for making the metal material surface into a mirror surface after the step is mentioned.

For example, in a general rough polishing process, an alumina abrasive grain or carbonized material that is dispersed in a solvent such as water while sandwiching a base material (polishing object) made of a metal material between upper and lower surface plates of a polishing apparatus and pressing from above. The substrate can be roughly polished by supplying free abrasive grains such as silicon abrasive grains and silicon oxide abrasive grains, that is, a polishing liquid, and rotating the upper and lower surface plates. By performing this rough polishing step, it is possible to remove deep scratches caused by mechanical grinding or the like of the substrate and improve smoothness. If it is the range of the above volume average particle diameters of an abrasive grain, it will become a polishing composition used suitably for such a rough | crude grinding | polishing process, and the effect of the removal of a deep flaw and improvement in smoothness can be acquired. .

In the present specification, the volume average particle diameter of the abrasive grains is defined as an integrated 50% particle diameter (D ₅₀ ) based on a volume-based particle size distribution. The D ₅₀ of the abrasive grains can be measured using a commercially available particle size measuring device. Such a particle size measuring apparatus may be based on any method such as a dynamic light scattering method, a laser diffraction method, a laser scattering method, or a pore electrical resistance method. As an example of a measuring method and apparatus for D _50, include measuring method and apparatus of example.

The lower limit of the content of abrasive grains in the polishing composition is preferably 0.1% by mass or more, more preferably 5% by mass or more, and further preferably 10% by mass or more. As the abrasive content increases, the polishing rate increases.

Further, the upper limit of the content of abrasive grains in the polishing composition is preferably 50% by mass or less, and more preferably 40% by mass or less. As the abrasive grain content decreases, the manufacturing cost of the polishing composition decreases, and it becomes easy to obtain a surface with few defects such as scratches by polishing using the polishing composition.

[Layered silicate compound]
The polishing composition of the present invention contains a layered silicate compound. In the polishing composition of the present invention, the layered silicate compound can exist in a state that causes steric hindrance between the abrasive grains, and thus has an effect of improving the dispersibility and redispersibility of the abrasive grains. . The layered silicate compound is basically based on a structure in which silicic acid tetrahedrons are connected in a plane, and the unit structure includes one or two silicic acid tetrahedral sheets and one alumina octahedron sheet. It is a structure characterized by the above. Between the layers (between unit structures), cations such as sodium, potassium and calcium are present. The layered silicate compound is a substance having a property that crystals are peeled off thinly.

The layered silicate compound used in the present invention may be a natural product, a synthetic product, a commercial product, or a mixture thereof. Examples of the synthesis method of the layered silicate compound include a hydrothermal synthesis reaction method, a solid phase reaction method, and a melt synthesis method.

Specific examples of the layered silicate compound include talc, pyrophyllite, smectite (saponite, hectorite, saconite, stevensite, bentonite, montmorillonite, beidellite, nontronite, etc.), vermiculite, mica (gold). Mica, biotite, chinwald mica, muscovite, paragonite, ceradonite, sea chlorite, etc.), chlorite (clinochlore, chamosite, nimite, penantite, sudowite, donbasite, etc.), brittle mica (clintonite, margarite, etc.) , Sulite, Serpentine (Antigolite, Lizardite, Chrysotile, Amesite, Clonsteadite, Burcellin, Greenerite, Garnierite, etc.), Kaolin (Kaolinite, Dickite, Nacrite, Halloysite, etc.) That. Among these, at least one of bentonite and hectorite is preferable. By being at least one of bentonite and hectorite, the intended effect of the present invention can be more effectively exhibited.

These layered silicate compounds may be used alone or in combination of two or more. Among them, from the viewpoint of being excellent in thixotropy and swelling properties and easier to improve the dispersibility and redispersibility of abrasive grains, it is preferable that the interlayer ions are cation compounds, and the interlayer ions are sodium ions. Bentonite (sodium bentonite), hectorite (sodium hectorite) and mica (sodium tetrasilicon mica) are preferred, and bentonite (sodium bentonite) whose interlayer ion is sodium ion is more preferred.

The lower limit of the content of the layered silicate compound in the polishing composition is preferably 0.01% by mass or more, and more preferably 0.1% by mass or more. Moreover, it is preferable that the upper limit of content of the layered silicate compound in polishing composition is 5 mass% or less, and it is more preferable that it is 2 mass% or less. Within such a range, the effect of the present invention can be obtained efficiently.

[Dispersion medium]
The polishing composition according to the present invention contains a dispersion medium for dispersing each component. As the dispersion medium, water is preferable. From the viewpoint of suppressing the inhibition of the action of other components, water containing as little impurities as possible is preferable. Specifically, after removing impurity ions with an ion exchange resin, pure water from which foreign matters are removed through a filter is used. Water, ultrapure water, or distilled water is preferred.

[PH of polishing composition]
The lower limit of the pH of the polishing composition of the present invention is not particularly limited, but is preferably 2.0 or more, more preferably 2.3 or more, and even more preferably 2.5 or more. Further, the upper limit of the pH is not particularly limited, but is preferably 12.0 or less, more preferably 10.0 or less, further preferably 7.0 or less, and 4.0 or less. It is particularly preferred. In preferable embodiment of this invention, pH is 2.0 or more and 7.0 or less. The layered silicate compound is characterized in that the surface charge of the crystal end face varies depending on the pH band. In particular, when the pH is in the range of 2.0 or more and 7.0 or less, the brass charge gradually takes on as the surface charge on the crystal end face becomes the acid side. Since the crystal layer surface is negatively charged regardless of the pH, the surface charge of the crystal end surface of the layered silicate compound and the negative portion of the crystal layer surface are attracted to form a card house structure. Since these are dispersed in a colloidal state, they become a three-dimensional barrier against abrasive grains. Therefore, the effect of improving the dispersibility of the abrasive grains can be obtained. On the other hand, when the pH is in the range of more than 7.0 and 12.0 or less, both the crystal end face and the crystal layer face of the layered silicate compound are negatively charged and repelled and dispersed. Since these are also dispersed in a colloidal state, an effect of becoming a three-dimensional barrier against abrasive grains and improving dispersibility can be obtained. However, since it is considered that the size of the layered silicate compound is smaller than that at the time of forming the card house structure, the pH is preferably 7.0 or less from the viewpoint of reducing the content of the layered silicate compound. Is preferably pH 2.0 or more.

When the object to be polished is an alloy material (for example, aluminum alloy, iron alloy, titanium alloy, nickel alloy, copper alloy, etc.), it is preferable that the polishing rate is high when the pH is in the acidic region. In addition, when the object to be polished is a resin material, it is preferable that the pH is in the acidic region, as described above, because the polishing rate is increased.

When the polishing composition has an alkaline pH range, the dispersibility and / or redispersibility of the abrasive grains can be improved by increasing the amount of the layered silicate compound added. From the viewpoint of improving the dispersibility and / or redispersibility of the abrasive grains by reducing the amount of the layered silicate compound added, the polishing composition preferably has an acidic pH range. That is, the pH of the polishing composition of the present invention is more preferably 2.0 or more and 7.0 or less. Since the layered silicate compound has a negative charge on the surface of the layer, if the pH is in the acidic region, the abrasive grains and the layered silicate compound can easily form a three-dimensional structure, and the layered silicate compound Even if the addition amount is small, it is considered that the dispersibility and / or redispersibility of the abrasive grains is likely to be improved.

The pH of the polishing composition can be adjusted by adding an acid or a salt thereof, or a base or a salt thereof described below.

[Acid or its salt]
The polishing composition of the present invention preferably contains an acid or a salt thereof. The acid or a salt thereof serves to adjust the pH of the polishing composition.

As the acid, either an inorganic acid or an organic acid can be used. 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, methoxy Phenylacetic acid, phenoxyacetic acid, methanesulfonic acid, ethanesulfonic acid, sulfosuccinic acid, benzenesulfonic acid, toluene Sulfonic acid, phenylphosphonic acid, such as hydroxyethyl-1,1-diphosphonic acid. Furthermore, examples of the salt include a group 1 element salt, a group 2 element salt, an aluminum salt, an ammonium salt, an amine salt, and a quaternary ammonium salt. These acids or salts thereof can be used alone or in combination. Among these, nitric acid and citric acid are preferable.

The content of the acid or its salt in the polishing composition may be appropriately adjusted so as to be in the above pH range.

[Base or salt thereof]
In order to adjust to the above pH range, a base or a salt thereof may be used. Examples of bases or salts thereof 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, magnesium hydroxide, Examples include Group 2 element hydroxides such as calcium hydroxide, and ammonia.

The content of the base or salt thereof in the polishing composition may be appropriately adjusted so as to be in the above pH range.

[Other ingredients]
The polishing composition of the present invention suppresses the corrosion of the polishing target, an oxidizing agent that oxidizes the surface of the polishing target, a water-soluble polymer that acts on the surface of the polishing target and the surface of the abrasive grains, if necessary. You may further contain other components, such as anticorrosive, a chelating agent, the preservative which has another function, and an antifungal agent.

Examples of the oxidizing agent include hydrogen peroxide, peracetic acid, percarbonate, urea peroxide, perchlorate, persulfate and the like.

Examples of water-soluble polymers include polycarboxylic acids such as polyacrylic acid, polysulfonic acids such as polyphosphonic acid and polystyrene sulfonic acid, polysaccharides such as chitansan gum and sodium alginate, cellulose derivatives such as hydroxyethyl cellulose and carboxymethyl cellulose, polyethylene glycol , Polyvinyl alcohol, polyvinyl pyrrolidone, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, sorbitan monooleate, oxyalkylene polymers having a single kind or plural kinds of oxyalkylene units. Moreover, the salt of said compound can also be used suitably as a water-soluble polymer.

Examples of the anticorrosive include amines, pyridines, tetraphenylphosphonium salts, benzotriazoles, triazoles, tetrazoles, benzoic acid and the like. Examples of chelating agents include carboxylic acid chelating agents such as gluconic acid, amine chelating agents such as ethylenediamine, diethylenetriamine, and trimethyltetraamine, ethylenediaminetetraacetic acid, nitrilotriacetic acid, hydroxyethylethylenediaminetriacetic acid, triethylenetetraminehexaacetic acid. , Polyaminopolycarboxylic chelating agents such as diethylenetriaminepentaacetic acid, 2-aminoethylphosphonic acid, 1-hydroxyethylidene-1,1-diphosphonic acid, aminotri (methylenephosphonic acid), ethylenediaminetetrakis (methylenephosphonic acid), diethylenetriaminepenta ( Methylenephosphonic acid), ethane-1,1-diphosphonic acid, ethane-1,1,2-triphosphonic acid, methanehydroxyphosphonic acid, 1-phosphonobutane-2,3,4-to Organophosphonic acid chelating agents such as carboxylic acid, phenol derivatives, 1,3-diketones and the like.

Examples of preservatives include sodium hypochlorite and the like. Examples of antifungal agents include oxazolines such as oxazolidine-2,5-dione.

[Method for producing polishing composition]
The method for producing the polishing composition of the present invention is not particularly limited, and can be obtained, for example, by stirring and mixing abrasive grains, a layered silicate compound, and other components as necessary in a dispersion medium. it can.

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

[Polishing method]
As described above, the polishing composition of the present invention is suitably used for polishing an object to be polished containing an alloy material and / or a resin material.

When polishing an object to be polished using the polishing composition of the present invention, it can be performed using an apparatus and conditions used for normal metal polishing. As a general polishing apparatus, there are a single-side polishing apparatus and a double-side polishing apparatus. In the single-side polishing apparatus, a polishing object (preferably a substrate-shaped polishing object) is held by using a holding tool called a carrier and polished. One surface of the polishing object is polished by rotating the surface plate by pressing a surface plate having a polishing cloth affixed to one surface of the object to be polished while supplying the composition for polishing. In a double-side polishing apparatus, a polishing object is held using a holder called a carrier, and a polishing plate is pressed against a surface opposite to the polishing object while a polishing composition is supplied from above, and these are pressed. The both sides of the object to be polished are polished by rotating in a relative direction. At this time, the polishing is performed by a physical action caused by friction between the polishing pad and the polishing composition and the object to be polished, and a chemical action that the polishing composition brings to the object to be polished.

An example of the polishing condition in the polishing method according to the present invention is a polishing load. In general, the higher the load, the higher the frictional force caused by the abrasive grains, and the higher the mechanical working force, the higher the polishing rate. The lower limit of the polishing load in the polishing method according to the present invention is not particularly limited, is preferably 20 g / cm ² or more, more preferably 50 g / cm ² or more. As the polishing load increases, the polishing rate increases because the mechanical processing characteristics improve. Further, the upper limit of the polishing load is preferably 1000 g / cm ² or less, and more preferably 500 g / cm ² or less. As the polishing load decreases, surface roughness of the polished surface is suppressed.

Further, as a polishing condition in the polishing method according to the present invention, a linear velocity in polishing (polishing linear velocity) can be mentioned. In general, the number of rotations of the polishing pad, the number of rotations of the carrier, the size of the object to be polished, the number of objects to be polished affect the linear velocity, but if the linear velocity is high, the frictional force applied to the object to be polished increases. The object is easily mechanically polished. In addition, frictional heat is generated by friction, and chemical action by the polishing composition may be increased. The lower limit of the polishing linear velocity in the polishing method according to the present invention is not particularly limited, but is preferably 10 m / min or more, and more preferably 20 m / min or more. Further, the upper limit of the polishing linear velocity is preferably 300 m / min or less, and more preferably 150 m / min or less. Within this range, in addition to obtaining a sufficiently high polishing rate, an appropriate frictional force can be imparted to the object to be polished. That is, in the present invention, the polishing linear velocity is preferably 10 m / min or more and 300 m / min or less, and more preferably 20 m / min or more and 150 m / min or less.

The polishing pad used in the polishing method using the polishing composition of the present invention is different in material properties such as polyurethane type, polyurethane foam type, nonwoven fabric type, suede type, etc., as well as differences in physical properties such as hardness and thickness. Further, there are various types including those containing abrasive grains and those containing no abrasive grains, and these can be used without limitation.

The polishing method according to the present invention can have a final polishing step using another polishing composition after the polishing step. Hereinafter, the finish polishing composition used in the finish polishing step will be described.

The abrasive grains contained in the finish polishing composition are preferably silicon oxide (silica), aluminum oxide, cerium oxide, zirconium oxide, titanium oxide, manganese oxide, silicon carbide, or silicon nitride. Of these, silicon oxide (silica) is preferable, and specific examples include colloidal silica, fumed silica, and sol-gel silica. Among them, fumed silica or colloidal silica is preferable from the viewpoint of obtaining the smoothness of the alloy surface more efficiently. Of these, at least one of aluminum oxide and silicon carbide is more preferable.

As a method for producing colloidal silica, known methods may be mentioned. For example, a method by hydrolysis of alkoxysilane described in pages 154 to 156 of “Science of Sol-Gel Method” by Sakuhana Sakuo (published by Agne Jofusha); described in JP-A-11-60232; A method of reacting methyl silicate and water by dropping methyl silicate or a mixture of methyl silicate and methanol into water, methanol and ammonia, or a mixed solvent composed of ammonia and an ammonium salt; A method described in Japanese Patent No. 48520, wherein an alkyl silicate koji is hydrolyzed with an acid catalyst, and then an alkali catalyst is added and heated to advance polymerization of silicic acid to grow particles; Japanese Patent Application Laid-Open No. 2007-153732 And a method of using a specific type of hydrolysis catalyst in a specific amount in the hydrolysis of alkoxysilane. Moreover, the method of manufacturing by ion-exchange of sodium silicate is also mentioned.

As a method for producing fumed silica, a known method using a gas phase reaction in which silicon tetrachloride is vaporized and burned in an oxyhydrogen flame can be mentioned. Further, fumed silica can be made into an aqueous dispersion by a known method. Examples of methods for making an aqueous dispersion include, for example, JP-A-2004-43298, JP-A-2003-176123, and JP-A-2002. And the method described in Japanese Patent No. 309239.

The average primary particle diameter of the abrasive grains contained in the final polishing composition is preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. When the average primary particle diameter of the abrasive grains is within the above range, the polishing rate of the object to be polished is improved. The average primary particle diameter of the abrasive grains contained in the finish polishing composition is preferably 400 nm or less, more preferably 300 nm or less, further preferably 200 nm or less, and preferably 100 nm or less. Most preferred. When the average primary particle diameter of the abrasive grains is within the above range, it is easy to obtain a surface with low defects and low surface roughness. When it becomes a problem that abrasive grains having a large particle diameter remain on the polished object after polishing, it is preferable to use abrasive grains having a small particle diameter not including the large particle diameter. In addition, the average primary particle diameter of the abrasive grains contained in the final polishing composition can be calculated from the measured value of the specific surface area by the nitrogen adsorption method (BET method).

The content of the abrasive grains in the finish polishing composition is preferably 1% by mass or more, and more preferably 2% by mass or more. When content of an abrasive grain exists in said range, the grinding | polishing speed | rate of the grinding | polishing target object by the composition for final polishing improves. The content of the abrasive grains in the finish polishing composition is preferably 50% by mass or less, and more preferably 40% by mass or less. When the content of the abrasive grains is within the above range, it is easy to obtain a polished surface with few scratches in addition to reducing the production cost of the finish polishing composition. In addition, the amount of abrasive grains remaining on the surface of the polished object after polishing is reduced, and the surface cleanliness is improved.

The pH of the final polishing composition varies depending on the type of polishing object to be polished. The pH in the finish polishing composition is adjusted with a known acid, base, or salt thereof. Among them, bases include amines such as aliphatic amines and aromatic amines, organic bases such as quaternary ammonium hydroxide, alkali metal hydroxides such as potassium hydroxide, alkaline earth metal hydroxides, and ammonia. Among these, potassium hydroxide or ammonia is preferable from the viewpoint of availability.

The lower limit of the pH of the finish polishing composition is preferably 2 or more, and more preferably 8 or more. As the pH of the finish polishing composition increases, the dispersibility of abrasive grains (for example, silica particles) improves. Further, the upper limit of the pH of the finish polishing composition is preferably 12.0 or less, and more preferably 11.5 or less. As the pH of the finish polishing composition decreases, the safety of the finish polishing composition is further improved, and it is also preferable from an economic viewpoint.

Like the polishing composition of the present invention, the finish polishing composition is an oxidant that oxidizes the surface of the polishing object, if necessary, a water-soluble polymer that acts on the surface of the polishing object or the abrasive grain surface, You may further contain other components, such as anticorrosive agent and chelating agent which suppress corrosion of a grinding | polishing target object, antiseptic | preservative which has another function, antifungal agent.

When polishing a polishing object using the polishing composition of the present invention, the polishing composition once used for polishing can be recovered and used again for polishing. As an example of a method for reusing the polishing composition, there is a method in which the polishing composition discharged from the polishing apparatus is collected in a tank and is circulated again into the polishing apparatus. Recycling the polishing composition can reduce the environmental load by reducing the amount of polishing composition discharged as waste liquid, and reduce the amount of polishing composition to be used by reducing the amount of polishing composition to be used. This is useful in that the manufacturing cost for polishing can be suppressed.

When the polishing composition of the present invention is recycled, some or all of abrasive grains, layered silicate compounds, and other additives consumed and lost by polishing are being used as a composition modifier. Can be added. In this case, as a composition regulator, it is good also as what mixed a part or all of an abrasive grain, a layered silicate compound, and another additive by arbitrary mixing ratios. By additionally adding a composition adjusting agent, the polishing composition is adjusted to a composition suitable for reuse, and polishing is suitably maintained. The concentration of the abrasive grains, layered silicate compound, and other additives contained in the composition modifier is arbitrary and is not particularly limited, but may be appropriately adjusted according to the size of the circulation tank and the polishing conditions. preferable.

The polishing composition of the present invention may be a one-component type or a multi-component type including a two-component type. The polishing composition of the present invention may be prepared by diluting the stock solution of the polishing composition, for example, 10 times or more using a diluent such as water.

The present invention will be described in further detail using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

(Preparation of polishing composition)
Dilute with water so that the abrasive grains have a content of 30% by mass, and add the dispersant (layered silicate compound or other compound in place thereof) to a content of 0.5% by mass at room temperature ( 25 ° C.) to prepare a dispersion. Next, citric acid or nitric acid was added as an acid to the dispersion, and the pH was adjusted to the values shown in Tables 1 to 6 below while confirming with a pH meter.

<Abrasive>
Aluminum oxide: α-ized 90 to 100% (The α-oxidized rate of aluminum oxide particles was measured by X-ray diffraction measurement using an X-ray analyzer (Ultima-IV, manufactured by Rigaku Corporation). (Calculated from the integrated intensity ratio)
Silicon _{carbide: GC # 3000 (D 50:} 4.0μm), GC # 1200 (D 50: 9.9μm)
The D ₅₀ of the abrasive grains was measured by a pore electrical resistance method using Multisizer III (manufactured by Beckman Coulter, Inc.).

<Layered silicate compound>
Na bentonite: sodium bentonite, viscosity of 300 mPa · s (measured value in 4% by mass aqueous dispersion, BM viscometer, 60 rpm, 25 ° C.), swelling power of 63 ml / 2 g
Steven sight: Viscosity of 1000 mPa · s (measured value in a 4% by mass aqueous dispersion, BM viscometer, 60 rpm, 25 ° C.), swelling power of 12 ml / 2 g
Na hectorite: sodium hectorite, particle size 3 μm (measured by laser diffractometer), aspect ratio 1000
Na tetrasilicon mica: sodium tetrasilicon mica, particle diameter 11 μm (measured by a laser diffractometer), aspect ratio 2000.

(Evaluation of dispersibility of abrasive grains)
The polishing composition was put in a 100 ml colorimetric tube (manufactured by AS ONE Co., Ltd.) up to a scale of 100 ml and allowed to stand for 1 hour. After standing, how much the height of the interface between the abrasive layer and the supernatant liquid was lowered compared with that before standing, and the number of scales lowered was measured. The smaller this value, the better the dispersibility.

(Evaluation of redispersibility of abrasive grains)
45 ml of the polishing composition was put in a 50 ml capacity PP container (manufactured by AS ONE Co., Ltd.) and allowed to stand for 60 hours. After standing, the PP container was turned upside down, and the number of times the bottom abrasive grains were removed was measured. The smaller the number of times, the better the redispersibility.

(Evaluation of polishing)
The polishing composition of each Example and each Comparative Example was used for polishing under the following polishing conditions, and the polishing rate was determined. Further, the surface roughness of each polished object after polishing was measured by the following method.

<Polishing conditions>
Polishing device: Single-side polishing device (plate diameter 380mm)
Polishing pad: Non-woven fabric type (with grooves)
Polishing load: 150 g / cm ²
Plate rotation speed: 50 rpm
Polishing linear velocity: 30 m / min Polishing time: 8 min
Supply rate of polishing composition: 35 ml / min.

<Polishing object>
Al alloy 6000 series: Three substrates having a size of 3.2 cm × 3.2 cm square and a thickness of 5 mm were set on the surface of the circular jig of the polishing apparatus at equal intervals in the rotation direction.

Al alloy 7000 series: One substrate having a size of 5.0 cm × 5.0 cm square and a thickness of 5 mm was set in the polishing apparatus.

SUS304: Three substrates having a diameter of 1 inch and a thickness of 5 mm were set on the surface of the circular jig of the polishing apparatus at equal intervals in the rotation direction.

Polycarbonate resin (siloxane copolymer grade, AG1950): Three substrates having a size of 3.2 cm × 3.2 cm square and a thickness of 5 mm were set at equal intervals in the rotation direction on the surface of the circular jig of the polishing apparatus.

<Polishing speed>
The polishing rate was calculated from the difference in mass of the polishing object before and after polishing.

<Surface roughness Ra>
The surface roughness Ra of the polished object after polishing was measured using a non-contact surface shape measuring instrument (laser microscope, VK-X200, manufactured by Keyence Corporation). The surface roughness Ra is a parameter indicating an average amplitude in the height direction of the roughness curve, and indicates an arithmetic average of the height of the surface of the polishing object within a fixed visual field. The measurement range by the non-contact surface shape measuring device was 285 μm × 210 μm.

(Comparison of various dispersants)
When abrasive grains of the evaluation of dispersibility and redispersibility of the polishing composition containing a layered silicate compound, or other compounds, as well as the evaluation of polishing, with abrasive grains D ₅₀ is 3.1 .mu.m (Table 1) and the case where abrasive grains having D ₅₀ of 8.0 μm were used (Table 2). Moreover, the comparative example 15 made the addition amount of ethylene glycol 10 mass%. The evaluation results are shown in Tables 1 and 2 below. In Tables 1 to 6 below, “-” indicates that the component was not added.

As apparent from Table 1 and Table 2 above, when a polishing composition containing a layered silicate compound was used (Example 1 in Table 1, Examples 2, 3, 4, 5 in Table 2), abrasive Good results were obtained in the dispersibility and redispersibility of the grains and the polishing performance. In particular, the dispersion of the abrasive grains while maintaining the polishing performance such as the polishing rate and Ra as compared with the comparative examples (Comparative Example 1 in Table 1 and Comparative Example 7 in Table 2) to which no layered silicate compound is added. It was found that the performance was improved. In addition, compared with the comparative examples using other dispersants (Comparative Examples 2 to 6 in Table 1 and Comparative Examples 8 to 15 in Table 2), the polishing composition of Example 1 maintained the polishing performance. It was found that the redispersibility of the abrasive grains was also improved.

(PH and D _{50 of} abrasive grains)
The pH of the polishing composition was changed to evaluate the dispersibility and redispersibility of the abrasive grains and the polishing performance. Further, the abrasive grains of the dispersibility and redispersibility by changing the abrasive grains D _50, as well as evaluating the polishing performance. In Example 9, the amount of sodium bentonite added was 0.8% by mass. The evaluation results are shown in Table 3 and Table 4 below. For comparison, Table 3 shows the results of Example 2 and Comparative Example 7, and Table 4 shows the results of Examples 1 and 2 and Comparative Examples 1 and 7, respectively.

As is apparent from Table 3 above, the polishing composition containing the layered silicate compound of the example was compared with the polishing composition of the comparative example to which the layered silicate compound was not added at various pHs. It was found that the dispersibility of the abrasive grains was improved while maintaining the polishing performance. Further, it was found that the polishing compositions of Examples 6 and 9 also improved the redispersibility of the abrasive grains as compared with Comparative Examples (Comparative Examples 17 and 18) having the same pH.

Furthermore, as is clear from Table 4, even when changing the abrasive grains D _50, polishing compositions of the Examples were found to improve abrasive grains dispersible. Compared with the polishing composition of Comparative Example 19, the polishing composition of Example 10 also improved the redispersibility of the abrasive grains.

(Silicon carbide, polishing object)
Silicon carbide was used as the abrasive grains, and the dispersibility, redispersibility, and polishing performance were evaluated. The evaluation results are shown in Table 5 below.

Also, the polishing performance was evaluated by changing various objects to be polished. The polishing composition used is the polishing composition of Example 2 and Comparative Example 7. For comparison, the results of Example 2 and Comparative Example 7 are also shown. The evaluation results are shown in Table 6 below.

As is apparent from Table 5 above, it was found that even when silicon carbide was used as the abrasive grains, the polishing compositions of the examples improved the dispersibility of the abrasive grains while maintaining the polishing performance. Compared with the polishing composition of Comparative Example 21, the polishing composition of Example 12 also improved the redispersibility of the abrasive grains.

Further, as apparent from Table 6 above, the polishing composition of Example 2 was more effective than the polishing composition of Comparative Example 7 while maintaining the polishing performance for various objects to be polished. It turned out that it becomes a composition which the dispersibility of the grain improved remarkably.

This application is based on Japanese Patent Application No. 2016-088407 filed on April 26, 2016 and Japanese Patent Application No. 2016-185783 filed on September 23, 2016. That disclosure is incorporated by reference in its entirety.

Claims (8)

1. Polishing composition containing abrasive grains, layered silicate compound, and dispersion medium.
2. The polishing composition according to claim 1, wherein the abrasive has a volume average particle size of 3.0 µm or more and 9.5 µm or less.
3. The polishing composition according to claim 1 or 2, wherein the pH is 2.0 or more and 7.0 or less.
4. The polishing composition according to any one of claims 1 to 3, wherein the abrasive grains are at least one selected from the group consisting of metal oxides and metal carbides.
5. The polishing composition according to any one of claims 1 to 4, which is used for polishing an object to be polished containing at least one selected from the group consisting of an alloy material and a resin material.
6. The polishing composition according to claim 5, wherein the alloy material contains at least one selected from the group consisting of an aluminum alloy and an iron alloy.
7. The aluminum alloy is an alloy containing 0.1% by mass or more of at least one metal element selected from the group consisting of magnesium, silicon, copper, zinc, manganese, chromium, and iron with respect to the entire aluminum alloy. The polishing composition according to claim 6.
8. The said iron alloy is an alloy containing 10 mass% or more of at least one metal element selected from the group consisting of chromium, nickel, molybdenum, and manganese with respect to the entire iron alloy. Polishing composition.