KR100753994B1 - Producing method for cerium-based glass polishing material and method for using the same - Google Patents

Abstract

The present invention relates to a high-dispersion slurry type cerium-based abrasive having a low scratch rate and excellent polishing rate and polishing characteristics, a manufacturing method capable of economically mass-producing it, and a polishing method using the same. The abrasive production method of the present invention consists of only the firing and pulverizing step, it is very economical to produce a large amount of abrasive in a short time by a simpler process. In addition, the highly dispersed slurry-type abrasive prepared by the method according to the present invention has a very small maximum particle size, low scratch rate, and excellent polishing rate and polishing characteristics. Unlike the conventional powder form, high scratch slurry can avoid deep scratches due to the accumulation tank in the polishing tank and pipes, which increases the yield of glass. Therefore, it can be used for polishing purposes in fields requiring high precision such as optical glass lenses, display glass, magnetic recording disk glass, liquid crystal glass, and the like. In addition, by improving the polishing process due to the above characteristics it is possible to obtain a yield improvement and polishing time and cost reduction effect.

Cerium oxide, abrasive, scratch, particle size

Description

Production method of cerium-based abrasive composition for glass polishing and method for use in polishing {PRODUCING METHOD FOR CERIUM-BASED GLASS POLISHING MATERIAL AND METHOD FOR USING THE SAME}

1 is a graph measuring the particle size distribution of the abrasive prepared in Example 1 of the present invention and the abrasive according to Comparative Examples 1 and 2. FIG.

Figure 2 is a photograph comparing the degree of scratch generation by the abrasive prepared in Example 1 of the present invention and the abrasive according to Comparative Example 1.

Figure 3 is a graph measuring the polishing rate of the abrasive prepared in Example 1 of the present invention and the abrasive according to Comparative Example 1.

-●-: Example 1

-■-: Comparative Example 1

Figure 4 is a photograph showing the result of polishing using an abrasive prepared by a conventional method for the LCD glass plate.

5 is a photograph showing the result of performing secondary polishing again after polishing using an abrasive prepared by a conventional method for an LCD glass plate.

Figure 6 is a photograph showing the result of polishing using the abrasive prepared in Example 1 of the present invention, the LCD glass plate.

Figure 7 is a photograph showing the result of performing secondary polishing again after polishing using the abrasive prepared in Example 1 of the present invention, the LCD glass plate.

The present invention relates to a cerium-based abrasive, a method for manufacturing the same, and a method of using the same, and more particularly, a highly dispersed slurry-type cerium-based abrasive having a low scratch rate and excellent polishing rate and polishing characteristics when used, and economically large quantities thereof. It relates to a manufacturing method that can be produced and a method of using the same for polishing.

In general, a powdered cerium-based abrasive mainly containing cerium oxide (CeO ₂ ) is used for polishing a glass material. Particularly, powdered cerium-based abrasives are used for polishing glass materials, which are recently used for electric and electronic devices such as glass for magnetic recording media such as hard disks and glass substrates of liquid crystal displays (LCDs) from conventional flat glass polishing. As a result, their applications are becoming wider. The reason why cerium-based abrasives are widely used for polishing glass materials is that high precision polishing surfaces can be obtained, and that a large amount of glass materials can be polished within a short time due to excellent cutting properties.

Such powdered cerium-based abrasives are classified into high cerium abrasives and low cerium abrasives by the content of cerium oxide. The high cerium abrasive is an abrasive having a relatively high cerium oxide content, containing at least 70% by weight of cerium oxide relative to the total weight of the rare earth oxide (hereinafter referred to as 'TREO'), and the low cerium abrasive having a cerium oxide content of TREO. It is relatively low abrasive about 50% by weight. Although these cerium oxide abrasives differ in cerium oxide content and raw materials, there is no significant difference in the production method after preparing the raw materials.

In general, the cerium-based abrasive is 1) roasting the raw material, 2) wet grinding and processing in a mine or the like, if necessary, and then chemically treated with hydrofluoric acid or ammonia fluoride, 3) the obtained slurry Filtration, drying, roasting, and 4) pulverization and classification.

However, in the conventional manufacturing method, roasting is performed twice, and the primary particles become large, which increases the hardness of not only granules but also its own powder during polishing, and causes a lot of scratches due to agglomeration of powders generated by the drying process. There was a problem. In addition, there was a problem that the manufacturing step is complicated and takes a long time and is not economical.

In addition, in the case of the conventional cerium abrasive prepared by the above method, since the powder is generally in powder form, the abrasive and water are mixed in the polishing tank at a constant ratio (1: 9) during use, and then the polishing is performed while being injected into the polishing machine. However, such powder-type abrasives have poor dispersibility (Zeta potential: -10 mV or less), so that they are deposited in the polishing tank, and the deposited particles having large grains are supplied to the polishing machine and then scratched during polishing. As a result, the yield of precision LCD glass is reduced to 75% or less. Therefore, in order to manufacture the precision LCD glass plate, the secondary polishing process must be essentially performed again, and as a result, the overall process time becomes long and there is a problem that the cost increase cannot be avoided.

The technical problem to be achieved by the present invention is to replace the dry powder-type abrasives that are currently used for polishing display glass plates, in particular LCD glass plate, low scratch occurrence rate in use, high dispersion rate and excellent polishing properties, The present invention provides an abrasive in the form of a high precision slurry, a method for economically manufacturing the same, and a polishing method for reducing the polishing process time and the polishing cost.

The present inventors have earned a lot of research in order to achieve the above technical problem, and as a result, has developed a method for producing a glass polishing abrasive through a very simple process, the abrasive produced using this method is highly dispersed, As a high-precision slurry form, it was confirmed that not only the scratch occurrence rate was excellent, but also the polishing rate and the polishing characteristics were excellent, and that the polishing yield could be increased by using such abrasives, thereby reducing the overall polishing process time and the polishing cost. Was completed.

In order to achieve the above technical problem, the present invention comprises the steps of calcining the trivalent cerium salt to change to tetravalent cerium oxide, the primary particle size is adjusted to 10 ~ 100nm; And mixing 10 to 90% by weight of tetravalent cerium oxide with 9 to 88% by weight of water and 0.1 to 20% by weight of a dispersant, followed by pulverization without drying to form a slurry having a particle size of 0.3 to 3 μm. Provided is a method of using the cerium-based abrasive composition prepared by the method for glass polishing for displays.

In addition, the present invention is the step of calcining the trivalent cerium salt to change to the tetravalent cerium oxide is adjusted to the primary particle size 10 ~ 100nm; And mixing 10 to 90% by weight of tetravalent cerium oxide with 9 to 88% by weight of water and 0.1 to 20% by weight of a dispersant, followed by pulverization without drying to form a slurry having a particle size of 0.3 to 3 μm. A method for producing a cerium-based abrasive composition for polishing display glass is provided.

Hereinafter, the present invention will be described in detail.

In the abrasive manufacturing method according to the present invention, first, the trivalent cerium salt is calcined as a raw material to change the tetravalent cerium oxide having a particle size of 10 to 100 nm. The trivalent cerium salt used as a raw material in the present invention is preferably at least one selected from the group consisting of cerium chloride, cerium nitrate, cerium carbonate, cerium hydroxide, cerium ammonium nitrate, cerium oxalate and the like. The process of changing cerium nitrate, which is a trivalent cerium salt, to tetravalent cerium oxide is shown in Scheme 1 below.

Ce (NO ₃ ) ₃ + 3H ₂ O → Ce (OH) ₃ + 3HNO ₃

CeO ₂ + 3HNO ₃ + 2H ₂ O → Ce (OH) (NO ₃ ) ₃ · 3H ₂ O

2Ce (OH) ₃ + 3O ₂ → CeO ₂ + 3H ₂ O ↑

Firing is preferably carried out for 10 minutes to 5 hours at a temperature of 400 ~ 1100 ℃, if the temperature is less than 400 ℃, the strength of the particles is weakened easily micronized and the polishing force is reduced, when the temperature exceeds 1100 ℃ the strength of the particles This is because it becomes stronger and the scratch occurrence rate increases.

In the present invention, the primary particle size is adjusted to 10 to 100 nm by firing under the conditions described above. By adjusting the primary particle size in this way, there is an advantage that the scratch occurrence rate by the finished abrasive can be reduced.

It is preferable that the weight ratio (CeO ₂ / TREO) of cerium oxide occupied in TREO is 40 to 99.99% by weight. In general, in the conventional abrasives, the ratio of cerium oxide to TREO is relatively low. However, in the present invention, the weight ratio of cerium oxide was high, and as a result, an abrasive having excellent polishing characteristics could be produced.

On the other hand, in the abrasive production method of the present invention after mixing 9 to 88% by weight of water and 0.1 to 20% by weight of the dispersant to 10 to 90% by weight of the tetravalent cerium oxide obtained by the firing process as described above, immediately without drying process Disintegrating is characterized in that to perform.

If the content of the dispersing agent is less than 0.1% by weight, the dispersing force is low, and cerium oxide particles are easily precipitated. Therefore, when the dispersant is more than 20% by weight, it is not easy to use it when the slurry is added. Since the problem of agglomeration of particles occurs due to the excessive amount of additives, it is preferable to add it in the content in the above range.

The dispersant is preferably selected from the group consisting of a water soluble anionic dispersant, a water soluble nonionic dispersant, a water soluble cationic dispersant, a water soluble amphoteric dispersant and a polymer dispersant.

Examples of the water-soluble anionic dispersant include lauryl sulfate triethanolamine, ammonium lauryl sulfate or polyoxyethylene alkyl ether triethanolamine.

As a water-soluble nonionic dispersing agent, polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxymethylene stearyl ether, polyoxyethylene oleyl ether, polyoxyethylene higher alcohol ether, polyoxyethylene octyl phenyl ether, polyoxyethylene Nonylphenyl ether, polyoxyalkylene alkyl ether, polyoxyethylene derivative, polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monopalmitate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan tristea Latex, polyoxyethylene sorbitan monooleate, polyoxyethylene sorbitan trioleate, tetraoleic acid polyoxyethylene sorbitan, polyethylene glycol monolaurate, polyethylene glycol monostearate, polyethylene glycol distearate, polyethylene glycol mono Oleate, polyoxyethylene And the like keel amine, polyoxyethylene hydrogenated castor oil or an alkyl alkanolamide.

Examples of the water-soluble cationic dispersant include coconut amine acetate, stearyl amine acetate, and the like.

Examples of the water-soluble amphoteric dispersant include lauryl betaine, stearyl betaine, lauryl dimethylamine oxide, 2-alkyl-N-carboxymethyl-N-hydroxyethyl imidazolium betaine, and the like.

In addition, polyvinyl acetal, polyvinyl formal, polyvinyl butyral, polyvinylpyrrolidone, polyvinylpyrrolidone iodine complex, polyvinyl (5-methyl-2-pyrrolidinone), polyvinyl (2-pipe) Lidinone), polyvinyl (3,3,5-trimethyl-2-pyrrolidinone), poly (N-vinylcarbazole), poly (N-alkyl-2-vinylcarbazole), poly (N-alkyl- 3-vinylcarbazole), poly (N-alkyl-4-vinylcarbazole), poly (N-vinyl-3,6-dibromocarbazole), polyvinylphenylketone, polyvinylacetophenone, poly (4- Vinylpyridine), poly (4-β-hydroxyethylpyridine), poly (2-vinylpyridine), poly (2-β-vinylpyridine), poly (4-hydroxyethylpyridine), poly (4-vinylpyridine) Lithium salt), poly (α-methylstyrene-co-4-vinylpyridinium hydrochloride), poly (1- (3-sulfonyl) -2-vinylpyridinium betaine co-ρ-styrenesulfonate potassium), poly ( N-vinylimidazole), poly (N-vinylimidazole), poly (4-vinylimidazole), poly (5-vinylimidazole), poly (1-vinyl-4-methyloxazole Dinon), polyvinylacetamide, polyvinylmethylacetamide, polyvinylethylacetamide, polyvinylphenylacetamide, polyvinylmethylpropionamide, polyvinylethylpropionamide, polyvinylmethylisobutylamide, polyvinylmethylbenzylamide , Poly (meth) acrylic acid, poly (meth) acrylic acid derivative, poly (meth) acrylic acid ammonium salt, polyvinyl alcohol, polyvinyl alcohol derivative, polyacrylate, polyacrylonitrile, polyvinyl acetate, poly (vinyl acetate-co- Methyl methacrylate), poly (vinyl acetate-co-pyrrolidine), poly (vinyl acetate-co-acetonitrile), poly (vinyl acetate-co-vinyl acrylate), poly (vinyl acetate-co-pyrrolidine ), Poly (vinyl acetate-co-acetonitrile), poly (vinyl acetate-co-N, N-diaryl cyanide), poly (vinyl acetate-co-N, N-diarylamine) or poly (vinyl acetate -co-ethylene) A it may also be used as a dispersing agent a polymer compound.

As such, after the calcination and disintegration step, the slurry becomes a slurry, and the mixture of the slurry may be further filtered.

The manufacturing method according to the present invention is characterized in that it consists only of the sintering and disintegration step as described above, it is possible to avoid agglomeration of the raw materials that can be caused by the drying process of the conventional powder type abrasive manufacturing method can lower the scratch occurrence rate.

The abrasive prepared by the method of manufacturing an abrasive according to the present invention as described above has a weight ratio (CeO ₂ / TREO) of cerium oxide in TREO is 40 ~ 99.99% by weight, particle size is 0.3 ~ 3㎛, as a slurry, scratch It has the advantage that the incidence is low and the polishing rate is high.

Conventional abrasives are in the form of dry powder when used, and the user directly mixes the abrasive and water in a predetermined ratio (1: 9). At this time, the dry powder form has a low dispersion force (Zeta potential: -10 mV or less), and the abrasive material accumulates in the tank, and the polishing yield decreases due to the increase in scratches caused by the deposited powder. did. However, since the abrasive prepared by the method according to the present invention is in the form of a slurry unlike the conventional dry powder, it is very excellent in dispersibility (Zeta potential: -40 mV or more) and there is no fear of being loaded into the tank. The incidence rate of is considerably lowered, which is advantageous in maintaining the polishing machine. In addition, in the case of a conventional abrasive, when the storage conditions (humidity, etc.) of the abrasive is not good, the granules may be formed due to moisture in the air. However, the abrasive according to the present invention does not occur because the abrasive is in the form of a highly dispersed slurry. have.

On the other hand, the polishing process of the display glass, especially LCD glass using a conventional dry powder abrasive, generally after the first polishing using a polishing machine, in order to eliminate the micro-scratches generated (polytex pad, Rohm & Hass) ) And second polishing is performed again. However, in the case of using the slurry-type abrasive prepared by the method according to the present invention, unlike the conventional process, only the first polishing can obtain the same level of polishing yield and abrasive as the conventional second polishing product, and thus the polishing process time and cost Can reduce the cost. In addition, when a high-precision display glass substrate is required, after the first polishing, if the same as the existing secondary polishing, there is an advantage that a glass substrate for display, in particular, a glass substrate for LCD, which is much more accurate than the existing process can be manufactured.

Hereinafter, the present invention will be described in detail by way of examples.

However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited to the following examples.

Example 1 Preparation of Abrasive Material

The trivalent cerium salt (95 wt% cerium oxide content in TREO) was heat-treated at 1000 ° C. in a kiln to change to tetravalent cerium oxide. 90% by weight of tetravalent cerium oxide, 9% by weight of water, 1% by weight of lauryl sulfate triethanolamine as a dispersant was stirred with a stirrer, and the size of the particles was 0.3 to 3㎛ using a wet mill (union). Adjusted to.

Example 2 Characterization of Abrasive Materials

2-1. Particle size measurement

10 g of the abrasive grain powder prepared in Example 1 was placed in 0.1% by weight aqueous sodium hexametaphosphate solution or 100 ml of distilled water, and dispersed for 2 to 3 minutes. The obtained dispersion was partially taken and the particle size distribution was measured by LS-230 (Coulter Counter), and the results are shown in FIG. 1. The particle size was measured using ultrasonic waves in general particle powder, but the abrasive was measured without using ultrasonic waves because it should be the same as the polishing condition.

As shown in FIG. 1, the abrasive prepared in the present invention compared to the abrasive prepared by the conventional method (Comparative Example 1 and Comparative Example 2) was confirmed that the average particle size is smaller than the conventional abrasive, and the maximum particle size is also very small. . In addition, it was confirmed that the concentration was narrow, showing uniform polishing characteristics.

2-2. Scratch evaluation

For the abrasive prepared in Example 1, after performing glass polishing under the polishing conditions described below, the glass was washed, the surface was measured by a polarization microscope (Olympus STM6), the results are shown in FIG.

As shown in FIG. 2, it was confirmed that scratches hardly occurred when the abrasive prepared in the present invention was used in comparison with the abrasive prepared in the conventional method (Comparative Example 1).

<Polishing condition>

1) Machine): Otsuka type single polisher, plate 1400mm

2) Workpiece: 1000pcs, soda lime glass

3) Platen Rotation Speed (rpm): 55

4) Pressure (psi): 100g / ㎠

5) Pad: Rohm & Hass MH14B

6) Solid content in Slurry (wt%): 10

7) Slurry Flow Rate (ml / min): 40ℓ / min

8) Polishing Time (min): 4pcs / 6min

2-3. Polishing rate evaluation

For the abrasive prepared in Example 1, after glass polishing under the same polishing conditions as in 2-2), the glass was washed, and the polishing rate was measured by a thickness gauge (Woritech WT-5890). The results are shown in FIG.

As shown in Fig. 3, when the abrasive (-?-) Produced in the present invention was used as compared with the abrasive (-?-) Produced by the conventional method, the polishing rate was high on average. In particular, after 30 times of polishing, the polishing rate was higher than that of the conventional abrasives.

Example 3 Abrasive Comparison Test

After polishing the LCD glass plate using the abrasive prepared in Example 1 and the abrasive prepared in the conventional method, the results are shown in FIGS. 4 to 7. The polishing process was performed using MHC14B Cerium pad from Rohm & Hass.

4 shows that the LCD glass plate is polished using an abrasive prepared by a conventional method, and a large number of scratches are generated even after polishing. Therefore, the second polishing had to be performed again with a Polytex product. FIG. 5 is a photograph showing the surface state after the second polishing of only the first polished LCD glass, and it was confirmed that scratches cannot be completely removed even after the second polishing.

On the other hand, Figure 6 is to polish the LCD glass plate in the same state using the abrasive of the present invention prepared in Example 1, it could be confirmed that the scratch hardly occurred after the first polishing, this state is shown in FIG. It showed the same surface condition as. That is, when performing the polishing process using the abrasive of the present invention, it was confirmed that the same result as the state after the secondary polishing in the conventional polishing process only by the primary polishing process. 7 is a result of performing the secondary polishing process using the abrasive of the present invention, it was possible to produce a high-precision LCD glass plate completely removed from the scratch. Therefore, when performing the polishing process using the abrasive of the present invention, it was confirmed that the polishing yield can be increased to reduce the polishing time and cost.

As described above, the abrasive manufacturing method of the present invention is composed of only the firing and grinding step, it is very economical to produce a large amount of abrasive in a short time by a simpler process. In addition, the highly dispersed slurry-type abrasive prepared by the method according to the present invention has a very small maximum particle size, low scratch rate, and excellent polishing rate and polishing characteristics. Unlike conventional powder forms, high-dispersion slurries can avoid deep scratches due to backlogs in the polishing tanks and pipes, which increases the yield of glass. Therefore, it can be used for polishing purposes in fields requiring high precision such as optical glass lenses, display glass, magnetic recording disk glass, liquid crystal glass, and the like. In addition, by improving the polishing process due to the above characteristics it is possible to obtain a yield improvement and polishing time and cost reduction effect.

Claims (8)

 Calcining the trivalent cerium salt to change the tetravalent cerium oxide whose primary particle size is adjusted to 10 to 100 nm; And mixing 10 to 90% by weight of tetravalent cerium oxide with 9 to 88% by weight of water and 0.1 to 20% by weight of a dispersant, followed by pulverization without drying to form a slurry having a particle size of 0.3 to 3 μm. A method of using the cerium-based abrasive composition produced by the method for glass polishing for displays. The method of claim 1, Characterized in that the weight ratio (CeO ₂ / TREO) of the cerium oxide to the total weight of the rare earth oxide (TREO) is 40 to 99.99% by weight A method of using a cerium-based abrasive composition for glass polishing for displays. The method of claim 1, The trivalent cerium salt is at least one member selected from the group consisting of cerium chloride, cerium nitrate, cerium carbonate, cerium hydroxide, cerium ammonium nitrate and cerium oxalate. A method of using a cerium-based abrasive composition for glass polishing for displays. The method of claim 1, The firing is carried out for 10 minutes to 5 hours at 400 ~ 1100 ℃ A method of using a cerium-based abrasive composition for glass polishing for displays.  Calcining the trivalent cerium salt to change the tetravalent cerium oxide whose primary particle size is adjusted to 10 to 100 nm; And 10 to 90% by weight of the tetravalent cerium oxide is mixed with 9 to 88% by weight of water and 0.1 to 20% by weight of the dispersant, and then pulverized without drying process to prepare a slurry of 0.3 ~ 3㎛ particle size Method for producing a cerium-based abrasive composition for polishing display glass. The method of claim 5, Characterized in that the weight ratio (CeO ₂ / TREO) of the cerium oxide to the total weight of the rare earth oxide (TREO) is 40 to 99.99% by weight Manufacturing method. The method of claim 5, The trivalent cerium salt is at least one member selected from the group consisting of cerium chloride, cerium nitrate, cerium carbonate, cerium hydroxide, cerium ammonium nitrate and cerium oxalate. Manufacturing method. The method of claim 5, The firing is carried out for 10 minutes to 5 hours at 400 ~ 1100 ℃ Manufacturing method.

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