KR100733918B1 - Method for preparing of ceramic paper and ceramic paper using the same - Google Patents

Abstract

A method for producing a ceramic paper is provided.

In the method for producing corrugated ceramic paper according to the present invention, a ceramic fiber having a length of 1 to 3 mm is dispersed in water and subjected to a ball milling process, thereby obtaining a ceramic fiber having a length of 50 to 500 μm and a uniform length distribution. After that, by using this to prepare a ceramic paper is characterized in that it is possible to improve the dispersion of the fiber and to form uniform pores in the final paper. According to the present invention, since the length of the ceramic fiber can be adjusted to 50 to 500 μm, the reproducibility is excellent, the ceramic paper having excellent pore uniformity can be produced, and the generation of the fracture is minimized, so that no classification process is required. The efficiency is excellent.

Ceramic Paper, Pore Uniformity

Description

Method for preparing ceramic paper and ceramic paper produced by the same {Method for preparing of ceramic paper and ceramic paper using the same}

Figure 1 shows the average diameter and distribution of pores in the ceramic paper prepared according to Example 1 of the present invention.

Figure 2 shows the average diameter and distribution of pores in the ceramic paper prepared according to Comparative Example 1.

3 is an optical micrograph of the ceramic fiber prepared according to Example 1.

4 is an optical micrograph of the ceramic fiber prepared according to Example 2.

5 is an optical micrograph of a ceramic fiber prepared according to Example 3.

6 is an optical micrograph of a ceramic fiber prepared according to Example 4.

7 is an optical micrograph of a ceramic fiber prepared according to Example 5.

8 is an optical micrograph of a ceramic fiber prepared according to Example 6.

The present invention relates to a ceramic paper, and more particularly to a method for producing a ceramic paper and a ceramic paper produced thereby.                         

Since the late 1970s, a diesel particulate filter (DPF) has been proposed and studied as a device for filtering particulate matter from diesel engines.DPF is divided into honeycomb monolith filter, ceramic fiber filter and metal filter. Can be. Among these, honeycomb monolith filter has a disadvantage of short life because it is vulnerable to high temperature thermal shock, and metal filter has advantages of price and ease of manufacture, but has a disadvantage of heat resistance and corrosion resistance. Research is actively being conducted.

The ceramic fiber filter has a porosity of 80% or more, has excellent ability to collect fine particles of 1 μm or less, has a strong strength against thermal shock due to the inherent elasticity of the fiber, and is used in the diesel engine because it can be structured in various forms. In addition to the dust filter may be used as a heat insulating material or a photocatalyst support.

In US Patent Nos. US 4652286, 5322537 and 6444006, paper is prepared from a slurry aqueous solution consisting of aluminosilicate or alumina ceramic short fibers, organic fibers and a water-soluble thermoplastic resin, and the dried paper is mixed with a colloidal alumina or alumina silicate solution. , Discloses an exhaust gas filter manufactured by shaping a three-dimensional structure using acrylic latex, polyvinyl chloride, polyvinyl alcohol, or starch as an organic component, but using a chopper to cut the ceramic fiber used above. Therefore, the length of the ceramic fiber is distributed over a wide range of 0.1 to 10 mm, which causes entanglement when dispersing the ceramic fiber, making it difficult to uniformly distribute the ceramic fiber and inferior in uniformity of ceramic filter pores. Can be sure of the reproducibility of There was a problem that the overall properties of the filter and decreased.

Therefore, the first technical problem to be achieved by the present invention is to overcome the problems of the prior art to provide a method for producing a ceramic paper excellent in uniformity of pores.

The second technical problem to be achieved by the present invention is to provide a ceramic paper manufactured by the above manufacturing method and excellent in uniformity of pores.

The present invention to achieve the first technical problem

(a) first dispersing the ceramic fiber 1 to 3 mm long in water;

(b) injecting the dispersion and the ball into a ball mill drum to mill to manufacture a ceramic fiber having a length of 50 to 500 µm; And

(c) preparing a ceramic green paper using a slurry solution including the ceramic fiber, the organic binder, and the inorganic binder prepared above; And

(d) heat treating the ceramic green paper to obtain a ceramic paper.

According to an embodiment of the present invention, the ceramic fiber used in step (a) may be alumina or aluminosilicate.

In addition, the content of the ceramic fiber in the step (a) may be 1 to 10 parts by weight based on 100 parts by weight of water based on solids.

According to another embodiment of the present invention, the ball used in step (b) may be a zirconia or alumina ball having a diameter of 1 ~ 10mm.

In addition, the amount of the ball introduced in the step (b) is 0.2 to 2% by volume relative to the ceramic fiber dispersion and may be used at a ball filling rate of 10 to 40% with respect to the ball mill drum volume.

In addition, the milling speed of the step (b) is preferably 10 ~ 300rpm.

According to another embodiment of the present invention, the amount of pulp in step (c) may be 5 to 30 parts by weight based on 100 parts by weight of the ceramic fiber.

In addition, the organic binder of step (c) is an acrylic binder, polyvinyl alcohol, amphoteric starch or a mixture thereof, and the amount of the organic binder may be 5 to 40 parts by weight based on 100 parts by weight of the ceramic fiber.

In addition, the inorganic binder of the step (c) is a silica sol, alumina sol, sericite or illite, the amount may be 5 to 30 parts by weight based on 100 parts by weight of the ceramic fiber.

According to a preferred embodiment of the present invention, the heat treatment temperature of step (d) may be 800 ~ 1200 ℃.

The present invention provides a ceramic paper, characterized in that produced by the manufacturing method in order to achieve the second technical problem.

According to a preferred embodiment of the present invention, the average flow pore size of the ceramic paper is 3 ~ 4㎛, pores of 2 to 12㎛ size may be present in a ratio of 90% or more of the total pore.

Hereinafter, the present invention will be described in more detail.

In the method of manufacturing ceramic paper according to the present invention, a ceramic fiber having a length of 1 to 3 mm is dispersed in water and subjected to a ball mill process to obtain a ceramic fiber having a length of 50 to 500 μm and a uniform length distribution, and then It is characterized in that the ceramic paper is used to improve the dispersion of the fiber and to form uniform pores in the final paper.

The ceramic fiber used in the present invention may include at least one of alumina or silica, such as alumina, alumina silicate, and the length of the ceramic fiber used in the ball mill process may be 1 to 3 mm, when the ratio is less than 1 mm. There is a problem that the high grinding efficiency is low, and when it exceeds 3mm, there is a fear that the length distribution of the crushed fiber is too large. On the other hand, the length of the fiber cut by the ball mill process is preferably 50 ~ 500㎛, if less than 50㎛ the strength of the produced paper is very weak, when more than 500㎛ fear of uniform dispersion of the fiber is difficult There is.

In the step (a), the content of the ceramic fiber is preferably 1 to 10 parts by weight based on 100 parts by weight of water, based on solid content. When it is less than 1 part by weight, there is a disadvantage in terms of economics of the process. Strong entanglement leads to difficulty in dispersion.                     

The ball used in the step (b) may be a zirconia or alumina ball having a diameter of 1 to 10mm, when the diameter of the ball is less than 1mm, the dispersing force is lowered so that cutting is not efficient, and when the ball exceeds 10mm, the cut ceramic fiber It is difficult to adjust the length of the film to 500 μm or less.

In addition, the amount of the ball introduced in the step (b) is preferably 0.2 to 2% by volume relative to the ceramic dispersion and 10 to 40% ball filling rate to the ball mill drum volume, the amount of the ball relative to the ceramic dispersion If it is less than 0.2 volume ratio, there is a problem that the cutting time is increased, and if it exceeds 2 volume ratio, there is a fear that the ratio of the fracture is increased, thereby weakening the strength of the paper and clogging pores during paper production. In addition, when used at a ball filling rate of less than 10% relative to the ball mill drum volume, there is a problem that the cutting efficiency is low, and when it exceeds 40%, there is a problem that the amount of fracture increases and the process efficiency is low.

In addition, the milling speed of the step (b) is preferably 10 ~ 300rpm, when the rotational speed is less than 10rpm is not preferable in terms of process efficiency, when exceeding 300rpm the cutting speed increases but the amount of the fracture is large There is a problem that increases. On the other hand, the milling time is not particularly limited, but is preferably 3 to 7 hours.

In the present invention, the ceramic green paper may be prepared using a papermaking method commonly used in the art, and the slurry solution used may be prepared by mixing the ceramic fiber with pulp, an organic binder, and an inorganic binder. Among the additive components, the amount of the pulp may be 5 to 30 parts by weight based on 100 parts by weight of the ceramic fiber. When the amount of the pulp is less than 5 parts by weight, the strength is not maintained after the green paper is produced. In this case, the porosity after firing may increase excessively and the strength may be weakened.

Examples of the organic binder used in the present invention include acrylic binders, polyvinyl alcohols, amphoteric starches, and mixtures thereof. The organic binders serve to improve the binding force between fibers and fibers and fibers and inorganic binders in a papermaking process. do. The amount of the organic binder may be 5 to 20 parts by weight based on 100 parts by weight of the ceramic fiber used. When the amount is less than 5 parts by weight, the binding force between the ceramic fiber and the inorganic binder is weakened. There is a possibility that the loss of, and because the bond strength between the fiber and the fiber is weak, there is a problem that it becomes difficult to maintain the structure of the paper. On the other hand, when the usage-amount of the said organic binder exceeds 20 weight part, the fluidity | liquidity of ceramic green paper will become large unnecessarily, and since adhesiveness will appear, workability will fall.

In addition, the inorganic binder used in the present invention is not particularly limited as long as it is commonly used in the art, and for example, silica sol, alumina sol, sericite or illite may be used. The inorganic binder is attached to the paper, and serves as an inorganic binder after heat treatment. The content of the inorganic binder is 5 to 30 parts by weight based on 100 parts by weight of the ceramic fiber. If the content of the inorganic binder is less than 5 parts by weight, the entirety of the inorganic paper may not be applied as the inorganic binder. Therefore, when the content of the inorganic binder exceeds 30 parts by weight, the pore size and porosity in the ceramic paper may be reduced by the inorganic binder particles. This can be degraded.

On the other hand, the ceramic green paper may be further subjected to the corrugation step, but the waveform device is not particularly limited as long as it is commonly used in the art, for example, the drum of the waveform device has a valley and pitch length of 2mm and 3mm, it can be used to control the surface temperature and the feed rate of paper can be used.

The heat treatment temperature of the step (d) is preferably 800 ~ 1200 ℃, when the temperature is less than 800 ℃ has a problem that the strength is weakened because the inorganic binder is difficult to play a role because the firing temperature is low, and when it exceeds 1200 ℃ There is a fear that a crystal phase with poor thermal stability may occur.

The average flow pore size of the corrugated ceramic paper produced in accordance with the present invention is preferably 3 to 4 μm, since the pore size is in this range to favor the removal of dust particles in microns. On the other hand, the uniformity of the pores of the ceramic paper according to the present invention is preferably such that the pores of 2 to 12㎛ size is present at a ratio of more than 90% of the total pores, when the uniformity of the pores is in the above range, Physical properties are excellent.

Hereinafter, the present invention will be described in more detail with reference to preferred examples, but the present invention is not limited thereto.

Example 1

5 g of fibers made of alumina silicate having an average diameter of 2 μm and an average length of 3000 μm were quantified and added to 95 g of water, followed by mixing. Next, a zirconia ball having a diameter of 5 mm was filled to 20% of the total ball mill drum volume, and then the ceramic fiber dispersion was added thereto. The amount of the balls was 0.5% by volume relative to the ceramic fiber dispersion. A ball mill cutting process was performed for 5 hours at a ball mill rotational speed of 150 rpm to obtain a ceramic fiber having an average length of 150 μm. 1 g of the aluminosilicate silicate fiber prepared above was added to 2 kg of water, followed by vigorous stirring to disperse the fiber, and after the fiber was dispersed, 0.5 g of alumina sol was added as an inorganic binder and stirring was continued to make even more dispersion. . Next, 6.7 g of 1.5 wt% aqueous pulp dispersion and 0.05 g of an acrylic emulsion (50 wt% solids) as an organic binder are added to the slurry, and the stirring is continued gently so that the solids in the slurry are evenly mixed. To prepare ceramic paper having a diameter of 9.5 cm and a thickness of 500 µm, and then heat-treated at 1000 ° C to obtain a final ceramic paper.

Example 2

In the same manner as in Example 1 except that the amount of ceramic fibers dispersed in water during the cutting process was filled with 30 g of the ball mill drum volume by using 1 g of ceramic fiber with respect to 99 g of water and 5 mm in diameter of zirconia balls. The cutting process was carried out to obtain a ceramic fiber having an average length of 100 μm, and the amount of balls was 0.7 by volume relative to the ceramic fiber dispersion. At this time, the amount of the fracture was used to obtain the final ceramic paper in the same manner as in Example 1.

Example 3                     

In the same manner as in Example 1, except that 9g of ceramic fiber was used for 90g of water and the zirconia ball having a diameter of 5mm was filled to 40% of the ball mill drum volume by using the amount of ceramic fiber dispersed in water during the cutting process. The cutting process was carried out to obtain a ceramic fiber having an average length of 80 μm, and the amount of balls was 1 volume ratio based on the ceramic fiber dispersion. Using this, the final ceramic paper was obtained in the same manner as in Example 1.

Example 4

A zirconia ball with a diameter of 10 mm was filled with 20% of the ball mill drum volume and the ball mill rotation speed was 300 rpm, and the average length was carried out by the same cutting process as in Example 1 except that the ball mill time was 3 hours. A 300 탆 ceramic fiber was obtained, the amount of balls being 0.5% by volume relative to the ceramic fiber dispersion. Using this, the final ceramic paper was obtained in the same manner as in Example 1.

Example 5

A ceramic fiber having an average length of 200 μm was obtained by performing a cutting process in the same manner as in Example 4, except that 10 mm diameter zirconia balls were filled with 30% of the ball mill drum volume. 0.7 volume ratio relative to the dispersion. Using this, the final ceramic paper was obtained in the same manner as in Example 1.

Example 6                     

A zirconia ball having a diameter of 10 mm was filled in 40% of the volume of the ball mill drum, and a cutting process was performed in the same manner as in Example 4 to obtain a ceramic fiber having an average length of 100 μm. 1 volume ratio relative to the dispersion. Using this, the final ceramic paper was obtained in the same manner as in Example 1.

Comparative Example 1

A ceramic paper was prepared in the same manner as in Example 1 except that the aluminosilicate fiber having a length of 1 to 3 mm was used directly without a grinding process.

Comparative Example 2

A ceramic fiber having an average length of 400 μm was obtained by performing the cutting process in the same manner as in Example 1, except that the zirconia ball having a diameter of 15 mm was filled to 60% of the volume of the ball mill drum. In the same manner as in 1, the final ceramic paper was obtained.

Comparative Example 3

A ceramic fiber having an average length of 350 μm was obtained by performing the cutting process in the same manner as in Example 1, except that the ball mill process speed was 400 rpm, and the final ceramic was obtained in the same manner as in Example 1 using the same. Got a paper.

Test Example 1

Light micrograph

3 to 8 show optical micrographs of the ceramic fiber in a state in which the grinding process is completed before preparing the ceramic paper in Examples 1 to 6 of the present invention. Referring to the drawings, it can be seen that the lengths of the crushed ceramic fibers are almost uniform, respectively, about 150 μm, 100 μm, 80 μm, 300 μm, 200 μm, and 150 μm.

Test Example 2

Pore size testing

The minimum pore size (diameter), the maximum pore size, and the average flow pore size of the pores of the ceramic paper prepared in Example 1 and Comparative Example 1 of the present invention were measured and shown in Table 1, FIG. 1 and FIG. 2. The measurement used a Capillary Flow Porometer (manufactured by Porous Materials).

Minimum pore size Maximum pore size Average flow pore size Example 1 2.11 13.53 3.45 Comparative Example 1 5.28 69.89 27.39

Unit: ㎛

As can be seen from Table 1, according to the present invention, the minimum pore size and the maximum pore size are much smaller than those of the comparative example, and the average flow pore size is also reduced to about 1/9. 1 and 2, according to the present invention, the average flow pore size is 3 to 4 μm, and since the pores having a size of 2 to 12 μm are present at a ratio of 90% or more of the total pores, the pore uniformity is excellent. You can see that.

Test Example 3                     

Measure the amount of fracture

The amount of the fracture in the ceramic fibers prepared by Examples 1 to 6 and Comparative Examples 2 and 3 was measured and shown in Table 2 below. The amount of the fracture was measured by visually grasping the number of fractures in the optical micrograph of the crushed fracture, the unit is the mass ratio to the crushed ceramic fiber mass.

Amount of fracture Example 1 0.05 Example 2 0.1 Example 3 0.3 Example 4 0.1 Example 5 0.2 Example 6 0.4 Comparative Example 2 0.5 Comparative Example 3 0.7

As described above, according to the present invention, since the length of the ceramic fiber can be adjusted to 50 to 500 μm, the reproducibility is excellent, the ceramic paper having excellent pore uniformity can be produced, and the generation of the fracture is minimized, thereby the classification process. Since it is not necessary, the manufacturing process is excellent in efficiency.

Claims (12)

(a) first dispersing the ceramic fiber 1 to 3 mm long in water; (b) injecting the dispersion and the ball into a ball mill drum to mill to prepare a ceramic fiber having a length of 50 to 500 µm; And (c) preparing ceramic paper before heat treatment using the slurry solution comprising the ceramic fiber, pulp, organic binder and inorganic binder prepared above; And (d) heat treating the ceramic paper before the heat treatment to obtain ceramic paper, The ball used in the step (b) is a method of producing a ceramic paper which is a zirconia or alumina ball having a diameter of 1 ~ 10mm. 2. The method of claim 1, wherein the ceramic fiber used in step (a) is alumina or aluminosilicate. The method of claim 1, wherein the content of the ceramic fiber in step (a) is 1 to 10 parts by weight based on solids, based on 100 parts by weight of water. delete The method of claim 1, wherein the amount of the ball introduced in step (b) is 0.2 to 2 parts by volume relative to the ceramic fiber dispersion and 10 to 40% by using a ball filling rate of the ball mill drum volume of the ceramic paper Manufacturing method. The method of claim 1, wherein the milling speed of the step (b) is a manufacturing method of the ceramic paper, characterized in that 10 to 300rpm. The method of claim 1, wherein the amount of pulp in step (c) is 5 to 30 parts by weight based on 100 parts by weight of ceramic fiber.        According to claim 1, wherein the organic binder of step (c) is an acrylic binder, polyvinyl alcohol, cationic starch or a mixture thereof, the amount of the use is 5 to 20 parts by weight based on 100 parts by weight of the ceramic fiber. Method for producing ceramic paper.        According to claim 1, wherein the inorganic binder of step (c) is silica sol, alumina sol, sericite or illite, the amount of the ceramic paper, characterized in that 5 to 30 parts by weight based on 100 parts by weight of the ceramic fiber. Manufacturing method. The method of claim 1, wherein the heat treatment temperature of the step (d) is 800 ~ 1200 ℃ manufacturing method of ceramic paper. delete delete

Images