WO2013035545A1

WO2013035545A1 - Abrasive grains, manufacturing process therefor, polishing slurry and process for manufacturing glass products

Info

Publication number: WO2013035545A1
Application number: PCT/JP2012/071349
Authority: WO
Inventors: 酒井　智弘; 有衣子吉田; 浩之朝長
Original assignee: 旭硝子株式会社
Priority date: 2011-09-09
Filing date: 2012-08-23
Publication date: 2013-03-14
Also published as: TW201321492A; JPWO2013035545A1

Abstract

The purpose of the present invention is to provide abrasive grains and a polishing slurry, both of which make it possible to polish an object to be polished at a high polish rate even when the amount of cerium oxide used is reduced. The present invention pertains to abrasive grains obtained by coating base particles with cerium oxide.

Description

Abrasive grains and manufacturing method thereof, polishing slurry and glass product manufacturing method

The present invention relates to abrasive grains, a method for producing the same, a polishing slurry, and a method for producing a glass product.

In the polishing process in the manufacture of glass products such as magnetic disks, liquid crystal glass, semiconductor substrates or photomasks for hard disk drives, improvement of the polishing rate by various means has been studied in order to improve productivity.

For example, Patent Document 1 discloses that the polishing rate can be improved by adding an additive to a polishing slurry containing ceria crystal microparticles or ceria-zirconia solid solution crystal particles, and good glass substrate surface properties can be obtained. It is shown.

Patent Document 2 shows that by containing cerium oxide particles produced using cerium carbonate having a primary particle diameter of 3 to 60 μm as a raw material, an abrasive capable of high-speed polishing without scratches can be obtained. Has been.

Patent Document 3 discloses that a polishing target composition is polished using a composite oxide containing cerium and zirconium in a polishing liquid composition, so that generation of scratches on the polishing target substrate can be suppressed and high speed can be achieved. It has been shown that smooth polishing is possible.

International Publication No. 2010/038617 Japanese Unexamined Patent Publication No. 2010-30041 Japanese Unexamined Patent Publication No. 2010-16064

As described above, cerium oxide is mainly used in the polishing process in the manufacture of glass products such as magnetic disks for hard disk drives, glass for liquid crystals, semiconductor substrates or photomasks because of the high polishing rate. However, cerium is difficult to supply stably because the area where it can be mined is limited, and in recent years the price has risen.

Therefore, an object of the present invention is to provide abrasive grains and polishing slurry that can polish an object to be polished at a high polishing rate with a small amount of cerium oxide used.

The inventors of the present invention can polish an object to be polished at a high polishing rate with a small amount of cerium oxide used by using abrasive grains having mother phase particles coated with cerium oxide for polishing the object to be polished. The present invention has been completed by finding out what can be done.

That is, the present invention is as follows.
1. Polishing abrasive grains in which matrix phase particles are coated with cerium oxide.
2. The mother phase particles are sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, carbonic acid. 2. The abrasive grain according to item 1, which is soluble in at least one aqueous solution selected from sodium and potassium carbonate.
3. 3. The abrasive grain according to item 1 or 2, wherein the matrix phase particle contains at least one oxide selected from the group consisting of manganese oxide and zinc oxide.
4). 4. The abrasive grain according to any one of items 1 to 3, wherein the cerium oxide coated on the matrix phase particles is 0.1% by mass to 25% by mass with respect to the matrix phase particles.
5. 5. The abrasive grain according to any one of items 1 to 4, wherein the cerium oxide coated on the matrix phase particles is 0.1% by mass to 20% by mass with respect to the matrix phase particles.
6). 6. The abrasive grain according to any one of items 1 to 5, wherein the specific surface area is 0.1 to 20 m ² / g.
7). 7. A polishing slurry comprising the polishing abrasive grain according to any one of 1 to 6 above.
8). A method for producing abrasive grains in which matrix particles are coated with cerium oxide, comprising the following steps (1) to (3) in sequence.
(1) A step of obtaining a cerium source aqueous solution by dissolving a cerium compound in water (2) A mother phase particle coated with the cerium source aqueous solution obtained in step (1) and coated with the cerium source aqueous solution Step (3) Step of firing mother phase particles coated with the aqueous cerium source solution obtained in step (2) to obtain mother phase particles coated with cerium oxide 9. 9. The method for producing abrasive grains according to item 8 above, wherein in step (2), the cerium source aqueous solution is sprayed on the mother phase particles to obtain mother phase particles coated with the cerium source aqueous solution.
10. 10. The method for producing abrasive grains according to item 8 or 9, wherein the cerium compound is at least one selected from the group consisting of cerium acetate, cerium nitrate, cerium hydroxide, and cerium sulfate.
11. 8. A method for producing a glass product, comprising a step of polishing glass using the abrasive grains according to any one of items 1 to 6 or the polishing slurry according to item 7.

According to the abrasive grains and the polishing slurry of the present invention, an object to be polished can be polished at a high polishing rate without using a large amount of cerium oxide.

FIG. 1 shows the X-ray profile of manganese oxide.

Hereinafter, the present invention will be described in detail.

[Abrasive grain]
The abrasive grains of the present invention are abrasive grains in which matrix phase particles are coated with cerium oxide, and include matrix phase particles and cerium oxide covering the matrix phase particles.

Examples of the mother phase particles include manganese oxide (Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ ), zinc oxide (ZnO), iron oxide (Fe ₃ O ₄ , Fe ₂ O ₃ ), copper oxide (Cu ₂ ). O, CuO), aluminum oxide (Al ₂ O ₃ ), silica (SiO ₂ ), chromium oxide (Cr ₂ O ₃ , CrO ₂ ) and zirconium oxide (ZrO ₂ ). These mother phase particles can be those commercially available.

The cerium oxide coated on the mother phase particles has a drawback that it has poor adhesion after polishing because it has high adhesion to the object to be polished and cannot be easily dissolved. Therefore, from the viewpoint of improving the cleanability after polishing, among these, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide It is preferable to use particles that are soluble in at least one aqueous solution selected from ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate as mother phase particles.

From sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate Examples of mother phase particles that are soluble in at least one selected aqueous solution include manganese oxide (Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ ), zinc oxide (ZnO), and iron oxide (Fe ₃ O _4). , Fe ₂ O ₃ ) and copper oxide (Cu ₂ O, CuO).

More specifically, manganese oxide (Mn ₃ O ₄ , Mn ₂ O ₃ , MnO ₂ ) can be dissolved by hydrochloric acid, sulfuric acid, nitric acid, ascorbic acid, hydrogen peroxide, or the like.

Zinc oxide (ZnO) can be dissolved by hydrochloric acid, nitric acid, sulfuric acid or the like.

Iron oxide (Fe ₃ O ₄ , Fe ₂ O ₃ ) can be dissolved by hydrochloric acid, nitric acid, sulfuric acid or the like.

Copper oxide (Cu ₂ O, CuO) can be dissolved by hydrochloric acid, nitric acid, sulfuric acid or the like.

These matrix particles may be used alone or in combination of two or more. Of these, manganese oxide or zinc oxide is more preferable. Manganese oxide or zinc oxide is highly soluble in acids, alkalis, oxidizing agents, or reducing agents, so using manganese oxide or zinc oxide for the matrix phase particles will not affect the workpiece. A high cleaning effect can be obtained with a cleaning liquid containing an acid, an alkali, an oxidizing agent, or a reducing agent.

Here, “soluble” means sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, peroxidation at room temperature for 1 hour. 0.1 to 1% by mass of mother phase particles were dissolved in an aqueous solution containing 0.01 to 2 mol% of one selected from hydrogen, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. Sometimes the amount of elution is 90% by mass or more. The solubility of the matrix phase particles can be tested according to the dissolution test described later in the Examples.

As mother phase particles, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, hydrogen peroxide, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, water In the cleaning step after polishing, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid are used in a cleaning process after polishing using at least one aqueous solution selected from potassium oxide, sodium carbonate and potassium carbonate. The object to be polished is cleaned with a cleaning liquid containing at least one selected from acids, formic acid, glycolic acid, acetic acid, hydrogen peroxide, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate. Thus, a high cleaning effect can be obtained without affecting the object to be polished.

The coating amount of the mother phase particles with cerium oxide is preferably 0.1 to 25% by mass, more preferably 0.1 to 20% by mass, further preferably 1 to 10% by mass, in terms of cerium oxide, and 1 to 5% by mass. % Is particularly preferred. When the coating amount is 0.1% by mass or more, an effect of improving the polishing rate can be obtained. When the coating amount is 25% by mass or less, the amount of cerium used can be reduced. be able to.

The specific surface area of abrasive grains of the matrix phase particles were coated with the cerium oxide is preferably 0.1 ~ ^20m 2 / g, more preferably ^{0.5 ~ 15m 2 / g, 1} ~ 10m 2 / g is more preferred. When the specific surface area of the abrasive grains is 0.1 m ² / g or more, polishing scratches due to coarse grains can be suppressed, and when it is 20 m ² / g or less, a sufficient polishing rate can be obtained. The specific surface area of the abrasive grains is measured by the method described later in the examples.

[Production method of abrasive grains]
The abrasive grains of the present invention can be produced by a production method that sequentially includes the following steps (1) to (3).
(1) Step of dissolving cerium compound in water to obtain cerium source aqueous solution (2) Covering mother phase particles with cerium source aqueous solution obtained in step (1), and coating mother phase particles coated with cerium source aqueous solution Step of obtaining (3) Step of firing mother phase particles coated with cerium source aqueous solution obtained in step (2) to obtain mother phase particles coated with cerium oxide Hereinafter, each step will be described.

(1) A step of dissolving a cerium compound in water to obtain a cerium source aqueous solution
As the cerium compound, cerium acetate, cerium nitrate, cerium hydroxide, or cerium sulfate is preferable in terms of availability and solubility in water. These cerium compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

The concentration of the cerium compound in the cerium source aqueous solution can be adjusted as appropriate in consideration of the amount of cerium oxide to be coated on the mother phase particles and the amount of the cerium source aqueous solution coated on the mother phase particles in step (2) described later. Good. It is preferable to set the concentration of the cerium compound in the cerium source aqueous solution to be equal to or lower than the solubility of the cerium compound because the cerium source aqueous solution can be uniformly coated on the mother phase particles in the step (2) described later.

In the step (2) described later, when the mother phase particles are coated with the cerium source aqueous solution by spraying the cerium source aqueous solution onto the mother phase particles, the concentration of the cerium compound in the cerium source aqueous solution should be 5 to 60% by mass. It is preferably 10 to 60% by mass.

In the step (2), when the mother phase particles are coated with the mother phase particles by immersing the mother phase particles in the cerium source aqueous solution, the concentration of the cerium compound in the cerium source aqueous solution is preferably 1 to 40% by mass. More preferably, the content is 1 to 20% by mass.

In the step (2), when the mother phase particles are coated with the mother phase particles by applying the mother phase particles to the cerium source aqueous solution, the concentration of the cerium compound in the cerium source aqueous solution is preferably 1 to 60% by mass. More preferably, the content is 1 to 40% by mass.

(2) Step of coating mother phase particles with cerium source aqueous solution obtained in step (1) to obtain mother phase particles coated with cerium source aqueous solution Step (2) is the cerium obtained in step (1) In this step, the mother phase particles are coated with the source aqueous solution, and the cerium compound is precipitated on the surface of the mother phase particles using water as a medium.

Examples of the method of coating the mother phase particles with the cerium source aqueous solution include spraying, dipping or coating. Among these, spraying does not require a drying step and is preferable from an industrial viewpoint.

(2-1) Spraying In the case of spraying, for example, the cerium source aqueous solution is sprayed on the matrix phase particles by spraying, spraying machine, etc., and the matrix phase particles are coated with the cerium source aqueous solution. At this time, the mother phase particles can be uniformly coated with the aqueous cerium source solution by stirring the mother phase particles for each spray.

Specific methods include, for example, a method in which matrix particles are placed in a plastic bag and a cerium source aqueous solution is sprayed with a spray.

Further, for example, the cerium source aqueous solution may be sprayed while being thermally dried with a rotary kiln and stirring the mother phase particles with a rotary machine, which is industrially advantageous.

The spray amount of the aqueous cerium source solution on the mother phase particles is preferably 0.1 to 40% by mass, more preferably 5 to 30% by mass, and 10 to 25% by mass with respect to the mother phase particles. More preferably.

When the spray amount is 0.1% by mass or more, the aqueous solution reaches the entire matrix phase particles, and uniform coating is possible. The amount of 40% by mass or less is preferable because it does not become paste or liquid and can be taken as it is to the firing step, so that the drying step can be omitted.

The spraying conditions are usually preferably 0 to 200 ° C.

(2-2) Immersion In the case of immersion, the mother phase particles are immersed in the cerium source aqueous solution to coat the mother phase particles with the cerium source aqueous solution. The amount of the mother phase particles immersed in the cerium source aqueous solution is usually preferably 1 to 60% by mass and more preferably 10 to 50% by mass with respect to the aqueous solution.

By setting the amount of matrix particles immersed in the aqueous cerium source solution to 1% by mass or more, the amount of water to be evaporated can be reduced, and by setting it to 60% by mass or less, the cerium compound can be uniformly coated. .

The immersion conditions are preferably 0.1 to 24 hours at 0 to 90 ° C.

The cerium compound can be deposited on the surface of the mother phase particles by coating the mother phase particles with the cerium source aqueous solution by immersion and then drying. The drying conditions are usually 80 to 200 ° C. and preferably 2 to 24 hours.

In the case of coating by dipping, the coating amount of the cerium compound on the mother phase particles after dipping the mother phase particles in the aqueous cerium source solution and drying is preferably 1 to 50% by mass with respect to the mother phase particles. It is more preferably 5 to 50% by mass, and further preferably 5 to 30% by mass.

When the coating amount is 1% by mass or more, the cerium compound is distributed over the entire matrix phase, and uniform coating can be achieved. When it is 50% by mass or less, cerium oxide does not precipitate alone.

(2-3) Application In the case of application, for example, the cerium source aqueous solution is applied to the mother phase particles with a rolling granulator or the like, and the mother phase particles are coated with the cerium source aqueous solution.

The coating amount of the aqueous cerium source solution on the mother phase particles is preferably 1 to 100% by mass, more preferably 5 to 80% by mass, and more preferably 10 to 60% by mass with respect to the mother phase particles. Is more preferable.

When the coating amount is 1% by mass or more and 100% by mass or less, the aqueous solution reaches the entire matrix phase particles, and uniform coating can be achieved.

The application conditions are usually preferably 0 to 90 ° C.

(3) Step of firing mother phase particles coated with cerium source aqueous solution obtained in step (2) to obtain mother phase particles coated with cerium oxide Step (3) is obtained in step (2). In addition, the mother phase particles coated with the aqueous cerium source solution are fired to oxidize the cerium compound, thereby obtaining mother phase particles coated with cerium oxide.

The firing temperature is preferably 300 to 1000 ° C, more preferably 400 to 1000 ° C, and still more preferably 400 to 800 ° C. By setting the firing temperature to 300 ° C. or higher, the cerium compound can be decomposed to deposit cerium oxide, and by setting it to 1000 ° C. or lower, the generation of coarse grains due to grain growth is suppressed, and the polishing abrasive with few scratches. Grains can be made.

The firing atmosphere is preferably in the air from the viewpoint of cost. The firing time is usually preferably 2 to 72 hours.

The coarse particles may be removed by classifying the fired product. Examples of the classification method include known methods such as a sieve or a classifier.

The abrasive grains in the present invention can be produced by the above steps (1) to (3), but other steps may be performed as long as they do not affect each step. Examples of other steps include the above-described drying or classification step. The abrasive grains in the present invention may be produced by a method that does not have one or more of the steps (1) to (3).

(Polishing slurry)
For example, the abrasive grains of the present invention can be dispersed in a dispersion medium such as water to form a polishing slurry. The abrasive grain concentration in the polishing slurry is preferably from 0.1 to 40% by mass, more preferably from 1 to 30% by mass, and even more preferably from 1 to 20% by mass. When the abrasive grain concentration is 0.1% by mass or more, a sufficient polishing rate can be obtained, and when it is 40% by mass or less, polishing can be performed efficiently.

Examples of the dispersion medium include water and alcohol. Examples of the alcohol include methanol, ethanol, 2-propanol and ethylene glycol.

A dispersant may be added to the slurry. As the dispersant, known ones can be used. Examples thereof include sodium citrate, sodium polyacrylate, ammonium polyacrylate, polyacrylic acid-maleic acid copolymer, pyridinecarboxylic acid and carboxymethylcellulose. Preferably mentioned.

The polishing slurry may be dispersed. A known method can be used for the dispersion treatment, and examples thereof include a homogenizer, an ultrasonic homogenizer, a ball mill, a bead mill, and a wet jet mill.

The pH of the polishing slurry is preferably 2 to 12, more preferably 5 to 12, and still more preferably 5 to 11. When the pH is 2 or more, polishing can be performed without dissolving abrasive grains, and when the pH is 12 or less, polishing can be performed without affecting the object to be polished.

The volume-based median diameter (D ₅₀ ) of the polishing slurry is preferably from 0.1 to 20 μm, more preferably from 0.5 to 20 μm, still more preferably from 0.5 to 10 μm. The median diameter of the polishing slurry is measured by the method described later in the examples.

When the median diameter of the polishing slurry is 0.1 μm or more, a sufficient polishing rate can be obtained, and when it is 20 μm or less, polishing scratches can be suppressed.

The polishing method in the present invention is not particularly limited. For example, the glass and the polishing cloth are brought into contact with each other, and the polishing cloth and the glass are relatively moved while supplying the polishing abrasive grains or the polishing slurry. It is preferable to grind to the shape. An example of the polishing cloth is a urethane polishing pad.

(Washing process)
The cleaning process should be appropriately selected depending on the glass product. For example, in manufacturing a glass substrate for a magnetic disk, the following cleaning process is exemplified.

The method for producing a glass product of the present invention includes sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, Including a step of cleaning the abrasive grains or polishing slurry adhering to the glass using a cleaning liquid containing at least one selected from potassium hydroxide, sodium carbonate and potassium carbonate (hereinafter also referred to as a cleaning liquid used in the present invention). Is preferred.

In the polishing step, as mother phase particles of abrasive grains, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, When one that is soluble in at least one aqueous solution selected from sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate is used, sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid By washing the glass with a cleaning solution containing at least one selected from acids, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate, An excellent cleaning effect can be obtained without influencing.

Sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and carbonic acid in the cleaning solution used in the present invention The total content of at least one selected from potassium is preferably 0.001 to 2 mol%, and more preferably 0.01 to 1 mol%.

Sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, sodium carbonate and carbonic acid By setting the content of at least one selected from potassium to 0.001 mol% or more in total, it is easy to maintain the elution amount. Moreover, the influence on glass can be suppressed by setting it as 2 mol% or less.

The cleaning liquid used in the present invention preferably contains a cleaning auxiliary. Examples of the cleaning aid include a surfactant for lowering the surface tension, and an acid having a buffering effect for stably maintaining pH.

Examples of the surfactant include nonionic surfactants such as acetylene diol and anionic surfactants such as sodium polyacrylate.

Further, examples of the acid having a buffering effect for stably maintaining pH include an acid having a pKa of 2 to 5 and having one or more carboxylic acids. Specifically, for example, citric acid can be cited as an acid that can be expected to have a buffering effect, but many other organic acids can be used.

The cleaning liquid used in the present invention preferably contains water as a solvent. Examples of water include deionized water, ultrapure water, charged ion water, hydrogen water, and ozone water. Since water has a function of controlling the fluidity of the cleaning liquid used in the present invention, its content can be appropriately set according to the target cleaning characteristics such as the cleaning speed, but usually 55 to 98 mass. % Is preferable.

In the cleaning step, it is preferable to perform cleaning by bringing the cleaning liquid into direct contact with glass. Examples of the method of bringing the cleaning liquid into direct contact with the glass include, for example, dip cleaning in which the cleaning liquid is filled in a cleaning tank, and glass is placed in the cleaning tank, a method of spraying the cleaning liquid onto the glass from a nozzle, and scrub cleaning using a sponge made of polyvinyl alcohol Etc. The cleaning liquid used in the present invention can be applied to any of the above methods, but dip cleaning using ultrasonic cleaning is preferred because more efficient cleaning can be performed.

In the cleaning step, the time for bringing the cleaning liquid into contact with the glass is preferably 30 seconds or more. By setting it to 30 seconds or more, a sufficient cleaning effect can be obtained.

In the washing step, the temperature of the washing solution may be room temperature, and may be used after being heated to about 40 to 80 ° C., but is preferably 80 ° C. or less. By setting the temperature of the cleaning liquid to 80 ° C. or lower, it is possible to prevent the acid, alkali, oxidizing agent or reducing agent contained in the cleaning liquid from causing thermal decomposition. Further, because of the configuration of the apparatus, when the cleaning liquid reaches a temperature close to 100 ° C., it becomes difficult to control pH by evaporation of water, and therefore, the temperature is preferably 80 ° C. or lower.

It is more effective to perform washing with water or an alkaline detergent after the washing step. Moreover, you may combine the washing | cleaning using water before the said washing | cleaning process.

(Other processes)
When the glass product is a glass substrate for magnetic disks, a glass substrate for high-quality liquid crystal display, etc., the glass main surface of the present invention after the cleaning step, It is preferable to include a final polishing step of polishing using a slurry containing colloidal silica abrasive grains.

Examples of glass products manufactured by the manufacturing method of the present invention include magnetic disk substrates for hard disk drives, glass substrates such as semiconductor substrates, photomask substrates, and display substrates, lenses, blue filter glasses for CCDs, and cover glasses. Can be mentioned. A magnetic disk can be manufactured by forming a magnetic recording layer on the main surface of a glass substrate for a magnetic disk manufactured by the manufacturing method of the present invention.

Hereinafter, although an example explains the present invention, the present invention is not limited to these.

(1) Preparation of abrasive grains and polishing slurry [Example 1]
2 L of distilled water and 37.5 g of glycine (manufactured by Kanto Chemical Co., Inc., reagent) were dissolved in a glass tank, and the water temperature was kept at 50 ° C. with a throwing heater while stirring. Thereto, 200 g of manganese (manufactured by Kanto Chemical Co., Ltd., reagent) was slowly added, and filtered through a sieve having an opening of 150 μm. The obtained solution was dried at 80 ° C. overnight and calcined at 700 ° C. for 8 hours in the air to obtain an oxide.

The obtained oxide was manganese oxide (Mn ₂ O ₃ ). The X-ray profile of the obtained manganese oxide was measured by TTR-III (manufactured by Rigaku Corporation). The result is shown in FIG.

Further, the specific surface area of the obtained manganese oxide was measured by ASAP2020 (manufactured by Shimadzu Corporation). The results are shown in Table 1.

20 g of the obtained manganese oxide, 378 g of distilled water and 2 g of a dispersant (manufactured by Lion Corporation, Polity A-550) were mixed, and a homogenizer was used for 15 minutes to form a polishing slurry. The abrasive grain concentration in the polishing slurry was 5% by mass, and the dispersant concentration was 0.5% by mass.

The volume-based median diameter (D ₅₀ ) of the obtained polishing slurry was measured with MT3300EXII (manufactured by Nikkiso Co., Ltd.), and the pH is shown in Table 1.

[Example 2]
30 g of manganese oxide obtained in Example 1 was put in a plastic bag, and 6.9 g of an aqueous solution of 16.9% by mass of cerium acetate monohydrate (manufactured by Kanto Chemical Co., Inc.) was sprayed by spraying. The spray amount was 23% by mass with respect to manganese oxide, and 2% by mass in terms of cerium oxide.

Then, it baked at 700 degreeC for 8 hours in air | atmosphere. The obtained oxide was Mn ₂ O ₃ coated with CeO ₂ . The X-ray profile of the obtained manganese oxide coated with cerium oxide was analyzed in the same manner as in Example 1. The result is shown in FIG. As shown in FIG. 1, a peak attributed to CeO ₂ was observed at 28.4 ° in addition to Mn ₂ O ₃ , confirming that cerium oxide was precipitated.

Further, the specific surface area of the obtained manganese oxide coated with cerium oxide was measured in the same manner as in Example 1. The results are shown in Table 1.

20 g of manganese oxide coated with cerium oxide thus obtained, 378 g of distilled water and 2 g of a dispersant (manufactured by Lion Corporation, Polity A-550) were mixed, and a homogenizer was used for 15 minutes to form a polishing slurry. The abrasive grain concentration in the polishing slurry was 5% by mass, and the dispersant concentration was 0.5% by mass.

The volume-based median diameter (D ₅₀ ) of the obtained polishing slurry was measured in the same manner as in Example 1, and the pH is shown in Table 1.

[Example 3]
20 g of zinc oxide (manufactured by Kokusei Kagaku Co., Ltd., reagent), 378 g of distilled water and 2 g of a dispersant (Lion Co., Ltd., Polyty A-550), which were baked at 700 ° C. for 8 hours in the atmosphere, were mixed, and a homogenizer was added for 15 minutes. A polishing slurry was obtained. The abrasive grain concentration in the polishing slurry was 5% by mass, and the dispersant concentration was 0.5% by mass.

[Example 4]
30 g of zinc oxide similar to Example 3 was sprayed with 5.4 g of an aqueous solution of 5.4% by mass of cerium acetate monohydrate (manufactured by Kanto Chemical Co., Ltd., reagent) by spraying. The spray amount is 18% by mass with respect to zinc oxide, and is 0.5% by mass in terms of cerium oxide. Then, it baked at 700 degreeC for 8 hours in air | atmosphere. The resulting oxide was ZnO which CeO ₂ is coated.

20 g of zinc oxide coated with cerium oxide obtained, 378 g of distilled water and 2 g of a dispersant (manufactured by Lion Corporation, Polity A-550) were mixed, and a homogenizer was used for 15 minutes to obtain a polishing slurry. The abrasive grain concentration in the polishing slurry was 5% by mass, and the dispersant concentration was 0.5% by mass.

[Example 5]
It put into the type | mold flask which makes 50 g of manganese oxides obtained in Example 1 and 100 g of 9.7 mass% cerium acetate monohydrate (Kanto Chemical Co., Ltd. reagent) aqueous solution, and dried, rotating a flask with an evaporator. The amount of the cerium acetate monohydrate aqueous solution was 200% by mass with respect to manganese oxide, and was 10% by mass in terms of cerium oxide. Then, it baked at 700 degreeC for 8 hours in air | atmosphere. The obtained oxide was Mn ₂ O ₃ coated with CeO ₂ .

20 g of manganese oxide coated with cerium oxide thus obtained, 378 g of distilled water and 2 g of a dispersant (manufactured by Lion Corporation, Polyty A-550) were mixed, and a homogenizer was used for 15 minutes to obtain a polishing slurry. The abrasive grain concentration in the polishing slurry was 5% by mass, and the dispersant concentration was 0.5% by mass.

[Example 6]
It put into the type | mold flask which makes 50 g of manganese oxides obtained in Example 1, and 150 g of 13.0 mass% cerium acetate monohydrate (product made from Kanto Chemical Co., Inc.) aqueous solution, It dried, rotating a flask with an evaporator. The amount of the cerium acetate monohydrate aqueous solution was 300% by mass with respect to manganese oxide, and was 20% by mass in terms of cerium oxide. Then, it baked at 700 degreeC for 8 hours in air | atmosphere. The obtained oxide was Mn ₂ O ₃ coated with CeO ₂ .

[Example 7]
A flask made of 50 g of zinc oxide (manufactured by High Purity Chemical Co., reagent) and 100 g of an aqueous solution of 9.7% by mass of cerium acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) baked at 700 ° C. for 8 hours in the atmosphere. The flask was dried while rotating the flask with an evaporator. The amount of cerium acetate monohydrate aqueous solution is 200% by mass with respect to zinc oxide, and 10% by mass in terms of cerium oxide. Then, it baked at 700 degreeC for 8 hours in air | atmosphere. The resulting oxide was ZnO which CeO ₂ is coated.

[Example 8]
A type flask comprising 50 g of zinc oxide (manufactured by High Purity Chemical Co., reagent) and 150 g of an aqueous solution of 13.0% by mass of cerium acetate monohydrate (manufactured by Kanto Chemical Co., Ltd.) baked in the atmosphere at 700 ° C. for 8 hours. The flask was dried while rotating the flask with an evaporator. The amount of the cerium acetate monohydrate aqueous solution is 300% by mass with respect to zinc oxide, and is 20% by mass in terms of cerium oxide. Thereafter, it was baked at 700 ° C. for 8 hours in the atmosphere. The obtained oxide was ZnO coated with CeO2.

(2) Dissolution test 30 mL of 1 mol / L sulfuric acid and 0.3 g of hydrogen peroxide, manganese oxide coated with cerium oxide obtained in Example 2 of (1), and coated with cerium oxide obtained in Example 4 30 mg of the prepared zinc oxide or cerium oxide (product name A10, Showa Denko KK) was put into a centrifuge tube, and stirred at room temperature for 1 hour on a rotating stand.

After stirring, use a centrifuge (device name: 5220, manufactured by Kubota Shoji Co., Ltd.), centrifuge at 3500 rpm for 10 minutes, remove the supernatant, add distilled water, centrifuge and remove the supernatant in the same way. I did it. Then, it was dried in a constant temperature bath at 80 ° C. for 3 hours. After drying, the residual amount of each abrasive grain was measured. From this value, the ratio (elution amount) of abrasive grains dissolved in the aqueous solution was determined.

That is, the amount of polishing abrasive grains dissolved in various aqueous solutions was expressed as a percentage (%), with the amount of polishing abrasive grains added to each aqueous solution minus the residual amount. The results are shown in Table 2.

As shown in Table 2, the abrasive grains obtained by using manganese oxide or zinc oxide as mother phase particles and coating the mother phase particles with cerium oxide have higher solubility in the cleaning liquid than cerium oxide. Indicated.

From this result, the abrasive grains in which manganese oxide and zinc oxide showing high solubility in a cleaning solution containing acid, alkali, oxidizing agent or reducing agent are used as mother phase particles, and the mother phase particles are coated with cerium oxide, It was suggested that the cleaning effect by the cleaning solution is high.

(3) Polishing Test A polishing test was performed using the polishing slurries of Examples 1 to 8 obtained in (1). Example 1 polishing slurry of Example 2, Example 2 polishing slurry of Example 4, Comparative Example 1 of Example 1 polishing slurry, Comparative Example 2 of Example 3 polishing slurry, Example 3 of Example 5 polishing slurry, Example 4 used the polishing slurry of Example 6, Example 5 used the polishing slurry of Example 7, and Example 6 used the polishing slurry of Example 8.

Glass was used for the object to be polished, the polishing pressure was 12 kPa, and the platen rotation speed was 40 rpm. A 12B single-side polishing machine (manufactured by Speed Fam) was used as the polishing machine, and FX8H-101U (manufactured by Fujibow) was used as the polishing pad.

The polishing slurry was circulated at 100 ml / min and polished for 20 minutes. The polishing rate (μm / min) was calculated from the weight difference before and after polishing. The results are shown in Table 3.

As shown in Table 3, when glass is polished with a polishing slurry containing abrasive grains coated with matrix particles with cerium oxide, the polishing rate is compared with a polishing slurry containing abrasive grains consisting only of matrix particles. Was found to be high.

It was also found that the coating amount of the mother phase particles with cerium oxide is preferably 0.1 to 25% by mass in terms of cerium oxide.

Although the invention has been described in detail using specific embodiments, it will be apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the invention. Note that this application is based on a Japanese patent application filed on September 9, 2011 (Japanese Patent Application No. 2011-197379), which is incorporated by reference in its entirety.

The abrasive grains and polishing slurry of the present invention are used in the manufacture of glass products such as magnetic disk substrates for hard disk drives, glass substrates such as semiconductor substrates, photomask substrates and display substrates, lenses, and blue filter glasses and cover glasses for CCD It can be used for the polishing process.

Claims

Polishing abrasive grains in which matrix phase particles are coated with cerium oxide.
The mother phase particles are sulfuric acid, hydrochloric acid, nitric acid, sulfamic acid, phosphoric acid, oxalic acid, tartaric acid, citric acid, formic acid, glycolic acid, acetic acid, ascorbic acid, hydrogen peroxide, ammonia, sodium hydroxide, potassium hydroxide, carbonic acid The abrasive grain according to claim 1, which is soluble in at least one aqueous solution selected from sodium and potassium carbonate.
The abrasive grain according to claim 1 or 2, wherein the matrix phase particles contain at least one oxide selected from the group consisting of manganese oxide and zinc oxide.
The abrasive grain according to any one of claims 1 to 3, wherein the cerium oxide coated on the matrix phase particles is 0.1 mass% to 25 mass% with respect to the matrix phase particles.
The polishing abrasive grain according to any one of claims 1 to 4, wherein the cerium oxide coated on the matrix phase particles is 0.1 mass% to 20 mass% with respect to the matrix phase particles.
The abrasive grain according to any one of claims 1 to 5, having a specific surface area of 0.1 to 20 m 2 / g.
A polishing slurry comprising the abrasive grains according to any one of claims 1 to 6.
A method for producing abrasive grains in which matrix particles are coated with cerium oxide, comprising the following steps (1) to (3) in sequence.
(1) A step of obtaining a cerium source aqueous solution by dissolving a cerium compound in water (2) A mother phase particle coated with the cerium source aqueous solution obtained in step (1) and coated with the cerium source aqueous solution (3) A step of firing mother phase particles coated with the aqueous cerium source solution obtained in step (2) to obtain mother phase particles coated with cerium oxide
The method for producing abrasive grains according to claim 8, wherein in the step (2), the cerium source aqueous solution is sprayed on the mother phase particles to obtain mother phase particles coated with the cerium source aqueous solution.
The method for producing abrasive grains according to claim 8 or 9, wherein the cerium compound is at least one selected from the group consisting of cerium acetate, cerium nitrate, cerium hydroxide, and cerium sulfate.
A method for producing a glass product, comprising a step of polishing glass using the abrasive grains according to any one of claims 1 to 6 or the polishing slurry according to claim 7.