JPH11347491A - Classification filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve both of classification efficiency and classification accuracy by consisting of the plane shape of the apertures of respective holes of a slender shape having a first length in a longitudinal direction and a second length in a short side direction orthogonal with this longitudinal direction. SOLUTION: This filter for classification is constituted by forming apertures 2 of respective holes over an entire surface of a base plate 1. The plane shape of the apertures 2 of the respective holes of the filter consists of the slender shape (rectangular shape) having the first length (a) in the longitudinal direction and the second length (b) in the short side direction orthogonal with the longitudinal direction. The second length (b) in the short side direction of the respective holes has the grain size of the granular material to be classified or the length near the same. Further, the first length (a) in the longitudinal direction of the apertures 2 preferably has the length at which the particles failing to pass the apertures 2 are rollable or movable along the longitudinal direction of the apertures 2. More specifically, the ratio of the first (a) of the apertures 2 to the second length (b) is preferably >=2, more preferably 100 to 1,000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter for sieving (filtering) fine particulate matter and classifying the same, and more particularly to a metal filter excellent in both classification efficiency and classification accuracy.

[0002]

2. Description of the Related Art Conventionally, as a method for classifying a true sphere or particles close to the sphere with high accuracy, a sedimentation method is known in which a particulate material to be classified is dispersed in an aqueous solvent and then sedimented to perform classification. Mainstream. This is because a filter capable of efficiently classifying fine particles without causing clogging has not been known.

[0003] For example, in a conventionally known microfiltration method using a membrane filter or a surface filter, clogging of the filter is liable to occur, and the classification efficiency is greatly reduced. Even if this filtration method is used in combination with a method such as backwashing, there is no way to eliminate the decrease in efficiency due to the backwashing operation. Such a problem of efficiency reduction in classification using a filter is particularly remarkable when the particle size distribution of the particles is relatively narrow.

[0004] On the other hand, in the method based on the sedimentation method, which is the mainstream in the past, the classification requires a long time, so that the classification efficiency is greatly reduced, and the production cost is disadvantageous.

[0005] In addition, it is possible to improve the classification speed by using the centrifugal separation method together with the sedimentation method.
Conversely, the use of centrifugal separation broadens the particle size distribution of the classified particles,
For this reason, there is a problem that classification accuracy is reduced.

Conventionally, in the sedimentation method, a method of increasing the sedimentation speed by selecting the type of a solvent to be used or a combination of a plurality of solvents to improve the efficiency has been proposed. There is still a problem that the diameter distribution is widened, and it is not always an effective method for improving classification accuracy.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a classification filter having improved classification efficiency and classification accuracy. It is assumed that.

[0008]

According to the present invention, there is provided a classifying filter for classifying particulate matter, comprising a substrate having a plurality of holes formed therein. The planar shape of the opening is characterized by having an elongated shape having a first length in a longitudinal direction and a second length in a transverse direction orthogonal to the longitudinal direction.

As described above, in the classification filter according to the present invention, since the shape of the opening of each hole of the filter is elongated, the particles to be classified quickly pass through the opening and do not pass through. Since the large particles can roll along the grooves in the longitudinal direction of the opening, clogging due to the large particles can be effectively prevented.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION A classifying filter according to the present invention is a classifying filter for classifying particulate matter, comprising a substrate on which a number of holes are formed, wherein the planar shape of the opening of each hole is as follows: It is characterized by having an elongated shape having a first length in a longitudinal direction and a second length in a short direction orthogonal to the longitudinal direction.

FIG. 1 is a plan view of the classifying filter, in which an opening 2 of the filter is formed over the entire surface of a substrate 1.

Although the material of the substrate is not particularly limited, when a filter is manufactured by an electrodeposition method as described later, a metal can be preferably used in terms of electrodeposition characteristics, durability, and manufacturing efficiency. Specifically, metals such as nickel, nickel-cobalt alloy, phosphorus nickel, nickel-palladium alloy, silver, copper, and gold can be preferably used. In the case of manufacturing by a usual photolithography method or the like, metals such as stainless steel, aluminum, and titanium having excellent corrosion resistance and rigidity can be preferably used.

FIG. 2 shows an enlarged plan view of the opening 2. As shown in FIG. 2, in the present invention, the opening 2 of each filter hole has an elongated shape (rectangle) having a first length a in the longitudinal direction and a second length b in the transverse direction orthogonal to the first length a. It has the shape of In the filter of the present invention, the second length b in the lateral direction of each hole has the particle size of the granular material to be classified or a length in the vicinity thereof. Further, it is preferable that the first length 21 in the longitudinal direction of the opening has a length that allows particles that cannot pass through the opening to roll or move along the longitudinal direction of the opening. Specifically, the first of the openings
The ratio of the length a to the second length b is 2 or more, further 100
It is preferably from 1,000 to 1,000.

As shown in these figures, the holes of the filter are usually regularly arranged in the vertical and horizontal directions on the substrate, but the present invention is not limited to only such a pattern. For example, it can be appropriately changed according to the type, size, or flow tendency of the granular material, and the application form of the filter.

The aperture ratio (the ratio of the total area of the openings to the surface area of the substrate functioning as a filter) of the classification filter of the present invention depends on the size, type, and physical properties of the granular material to be classified. Can be selected as appropriate, but is usually preferably about 10 to 60%.

In the present invention, the cross-sectional shape of the filter opening is not particularly limited, but is determined in consideration of the ease with which particles can pass and the ease with which particles that cannot pass can roll in the longitudinal direction. be able to. In consideration of these points, for example, as shown in FIGS. 3, 4 and 5, in the cross-sectional shape in the short direction of each hole, both sides or at least one side of the substrate is wider than the narrowest portion. Is preferred.

The thickness of the filter can be appropriately selected according to the purpose, but is usually preferably 10 to 50 μm.

Next, a method for producing a classification filter according to the present invention will be described.

In the classification filter according to the present invention, for example, a resist pattern for forming a filter opening is formed on a substrate for electrodeposition, and a metal layer is formed on a substrate other than the resist portion by electrodeposition. By separating the electrodeposited metal layer thus formed from the substrate, a classification filter of the present invention in which a predetermined opening pattern is formed can be obtained.

Further, in the above manufacturing method, after the electrodeposited metal layer is peeled from the electrodeposition substrate, a predetermined metal coating layer is formed by electrodeposition on both the front and back surfaces of the peeled material and the inner wall surface of the opening. In addition, a filter in which the cross-sectional shape of the opening is a thread winding shape can be obtained.

FIG. 6 is a process sectional view showing a method of manufacturing the filter of the present invention by an electrodeposition method. As shown in FIG. 6A, a resist is uniformly applied on a substrate 21 for electrodeposition by an application method such as a spinner method, a roll coating method, and a dipping and pulling method, and is heated and dried to form a resist layer 22. I do. In addition to the above, a specific resist film may be laminated with a hot roll to form a resist layer.

As the electrodeposition substrate 21, a stainless steel plate,
A metallized plate such as a nickel plate, a copper plate, a phosphor bronze plate, a brass plate, or a quartz plate or a glass plate having good flatness, and a thin film that can be plated such as stainless steel, nickel copper, tin oxide, or indium oxide is deposited or sputtered. A method formed by such a method can be used. In this case, the thickness of the substrate is 0.1 mm to 3 mm.
A degree is desirable. As the resist material, a negative resist such as a rubber-based resist, a PVA-based resist, a cinnamic acid-based resist, a casein-based resist, an acrylic resist, or a positive resist such as a novolak-based resist can be used.

Next, as shown in FIG. 5B, a mask 24 having a desired pattern 23 formed on the resist layer is closely adhered or overlapped at a fixed interval, and irradiated with ionizing radiation 25. In this case, it is a matter of course that the mask in the case of using a negative resist forms a pattern so that ionizing radiation passes through a desired hole, and in the case of using a positive resist, the mask forms a pattern of ionizing radiation. Used with a positive pattern formed to block the light.

Subsequently, the film is developed with a predetermined developing solution, rinsed with a predetermined rinsing liquid, dried, and further subjected to post-baking for hardening the resist film. Further, as shown in FIG. 6D, for example, nickel is electrodeposited to a desired thickness by electrodeposition means, for example, electroplating, and a thin plate layer (nickel plating layer) 26 is formed by electrodeposition. In this case, by performing electrodeposition so that the plating layer is raised above the resist pattern, a funnel-shaped opening having one gentle opening can be formed. Finally, the nickel plating layer 26 is peeled from the substrate to obtain a classification filter of the present invention in which a desired opening 27 is formed as shown in FIG.

The classification filter of the present invention can be manufactured by forming a predetermined opening pattern by applying a normal photoresist method to a thin metal plate in addition to the above-described electrodeposition method.

The classification filter according to the present invention may be configured as a device that improves classification accuracy or that can simultaneously classify particles having different particle diameters by combining the filters in a plurality of stages. Can also.

FIGS. 7 and 8 are perspective views showing an example of such a classification device. In the device shown in FIG.
The filter 7 for classification according to the present invention in a fixed housing 70
This is an example in which 1a, 71b, and 71c are alternately arranged.

In the example of FIG. 8, funnel-shaped filters 8181a, 81b, and 8 are provided in a cylindrical housing 80.
1c and 81d are arranged in combination, and the particles classified by each filter are taken out from the outlet 82.
a, 82b, 82c and 82d. In each of the cases of FIGS. 7 and 8, by appropriately selecting the size of the opening of each filter, it is possible to effectively classify and collect particulate matter having different particle diameters.

In the present invention, the type and size of the granular material to be classified are not limited, and any particles, for example, polymer particles or inorganic particles can be classified. For example, particles having a particle size of about 3 to 10 μm, for example, polystyrene particles obtained by emulsion polymerization, seed polymerization, dispersion polymerization, etc., polymer particles such as acryl-styrene copolymer, and inorganic particles such as silica particles are efficiently classified. can do.

[0030]

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited to the following embodiments.

Example 1 A casein-based negative resist (FRN015) manufactured by Fuji Pharmaceutical Co., Ltd. was applied on a stainless steel (SUS304 material) having a thickness of 0.5 mm and a size of 200.times.300 mm by a dipping and pulling method. After drying for 30 minutes, a uniform resist film was obtained.

Next, a mask was superimposed on the resist film, and a pattern was drawn by a printer. At this time,
Exposure was carried out with a KW mercury lamp at a wavelength of 365 nm for 2-3 minutes.

Subsequently, the exposed resist film is coated with 40 to 5
After developing with hot water at 0 ° C., the substrate was rinsed with water and spin-dried to prepare a substrate on which a number of rectangular resist patterns each having a thickness of 3 μm, a length in the short direction of 25 μm, and a length in the long direction of 120 μm were arranged.

Next, the substrate was baked at 200 to 300 ° C. for several minutes, immersed in a nickel sulfamate bath, and plated with nickel to a thickness of 15 μm on the surface on which the resist pattern was formed by electroplating. The composition and plating conditions of this nickel sulfamate bath are shown below. Nickel sulfamate 400g / l Boric acid 30g / l pH 4.0 Bath temperature 50 ° C Current density 3A / dm2 Time 30min

Subsequently, after drying at 80 ° C. for 5 minutes, the plated nickel is peeled off, and a filter having a large number of holes of 5 μm in the transverse direction and 100 μm in the longitudinal direction at the narrowest portion of the 15 μm-thick hole is formed. Obtained. The cross-sectional shape of the filter at this time was a morning glory as shown in FIG.

Example 2 A casein-based negative resist (FRN015) manufactured by Fuji Pharmaceutical Co., Ltd. was applied on a stainless steel (SUS304 material) having a thickness of 0.5 mm and a size of 200 × 300 mm by a dipping and pulling method. The pulling speed at this time was lower than that in Example 1. Thereafter, drying was performed at 45 ° C. for 30 minutes to obtain a uniform resist film.

Next, a mask was overlaid on the resist film, and a pattern was drawn by a printer. At this time, 3KW
Was exposed to ultraviolet light having a wavelength of 365 nm for 2 to 3 minutes using a mercury lamp.

Subsequently, the exposed resist film is coated with 40 to 5
After development with hot water at 0 ° C., the substrate was rinsed with water and spin-dried to prepare a substrate on which a number of rectangular resist patterns each having a thickness of 6 μm, a length in the short direction of 15 μm, and a length in the long direction of 110 μm were arranged.

Next, the substrate was baked at 200 to 300 ° C. for several minutes, immersed in a nickel sulfamate bath, and plated with nickel to a thickness of 5 μm on the resist-formed surface by electroplating. The composition and plating conditions of this nickel sulfamate bath are shown below. Nickel sulfamate 400g / l Boric acid 30g / l pH 4.0 Bath temperature 50 ° C Current density 3A / dm2 Time 12.5min

Subsequently, after performing a heat-drying treatment at 80 ° C. for 5 minutes, the plated nickel is peeled off to give a thickness of 5 μm.
Thus, a metal foil having a large number of holes having a length in the short direction of 15 μm and a length in the long direction of 110 μm was obtained.

This foil was fixed to a frame, nickel was plated from both sides, and the width of the narrowest portion of 15 μm in the width direction of the narrowest portion was 5 μm.
m, a nickel filter having many holes having a length of 100 μm in the longitudinal direction was completed. The composition of the nickel sulfamate bath and plating conditions at this time are as follows. Nickel sulfamate 400g / l Boric acid 30g / l Hypophosphorous acid reader 3g / l pH 4.0 Bath temperature 50 ° C Current density 3A / dm2 Time 25min

Since the nickel film contained phosphorus at this time, a filter having good corrosion resistance could be obtained. The cross section of the hole of the filter in this example had a thread-like shape as shown in FIG.

Example 3 Acrylic resist (PMER-N) manufactured by Tokyo Ohka Co., Ltd. was applied on a stainless steel (SUS304 material) having a thickness of 0.5 mm and a size of 200 × 300 mm by a Miyabar coating method.
The film was held horizontally at 30 ° C. for 30 minutes and dried by heating to obtain a uniform resist film having a thickness of 18 μm.

Next, a pattern was drawn by overlapping a mask on the substrate on which the resist was formed. At this time, a 3KW mercury lamp with a light source printer having moderate parallelism
The film was exposed to ultraviolet light of 5 nm at an exposure amount of 250 mJ / cm2.

Subsequently, the exposed resist film is developed with a predetermined developing solution, and further rinsed to have a thickness of 18 μm, a length in the short direction of 9 μm on the substrate surface, a length of 5 μm on the upper portion, and a length in the longitudinal direction. Is 104 μm on the substrate surface, and the dimension of the resist upper part is 5 μm in the lateral direction and 100 μm in the longitudinal direction.
A substrate having a number of trapezoidal resist patterns was prepared.

Next, the plating substrate was immersed in a nickel sulfamate bath, and the resist surface was plated by electroplating so that the nickle thickness became 15 μm. The composition and plating conditions of this nickel sulfamate bath are shown below. Nickel sulfamate 400 g / l Nickel chloride 3 g / l Boric acid 30 g / l Additives Appropriate amount pH 4.0 Bath temperature 50 ° C Current density 4 A / dm 2 hours 30 minutes

Subsequently, after isolating the resist, the resist was dried at 80 ° C. for 5 minutes, and nickel was peeled off to remove the nickel to a thickness of 15 μm, a shortest length of the narrowest portion of the hole of 5 μm, and a longitudinal length of 100 μm. In addition, a filter having a large diameter as shown in FIG. 5 was obtained.

Classification Test A classification test was performed using a conventional surface filter and the metal filter according to the present invention. Furthermore, a comparative test by a conventional sedimentation method was also performed.

As the filter of the present invention, the filter obtained in Example 1 was used. On the other hand, as a conventional filter, a surface filter (manufactured by Millipore Co., Ltd .;
μm)).

As the granulated material to be classified, a granular material of an acrylic / styrene copolymer (aqueous dispersion having a solid content of 10% by weight / 100 g) was used. The particle size distribution width of the granular material is 4.
5 to 7.5 μm.

The filter (5 μm) according to the first embodiment of the present invention
Classification was carried out according to (m slit width, length 100 μm), and classified particles having an average particle size of 5.0 ± 0.5 μm were obtained. Classification could be performed quickly and with high accuracy, and the yield was 8.3 g.

On the other hand, when the same classification was performed using a conventional surface filter having a pore size of 5 μm, clogging occurred soon after the filter operation was started, and the yield was 3.5 g.
(Distribution: average particle size 5.0 ± 0.5 μm).

Further, the above-mentioned granular material is subjected to sedimentation by 24
Classification was performed by slow sedimentation over a period of time. As a result, the particle size distribution of the obtained granules was wide, ranging from 4.5 to 6.3 μm, and the yield was 5.8 g.

[0054]

As is clear from the results of the above embodiment, in the filter according to the present invention, the planar shape of the opening of the filter has the first length in the longitudinal direction and the second shape in the short direction orthogonal to the longitudinal direction. Because it consists of an elongated shape with a length
Excellent effects are achieved in both classification efficiency and classification accuracy.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a classification filter of the present invention.

FIG. 2 is a partially enlarged view of the classification filter shown in FIG.

FIG. 3 is a cross-sectional view of an opening of a classification filter according to an embodiment of the present invention.

FIG. 4 is a cross-sectional view of an opening of the classification filter according to the embodiment of the present invention.

FIG. 5 is a sectional view of an opening of the classification filter according to the embodiment of the present invention.

FIG. 6 is a process cross-sectional view showing one example of a method for producing a classification filter of the present invention.

FIG. 7 is a perspective view showing a classification device configured by combining classification filters according to the present invention.

FIG. 8 is a perspective view showing a classification device configured by combining classification filters according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 filter opening 21 electrodeposition substrate 22 resist layer 23 mask pattern 24 mask 25 ionizing radiation 26 nickel plating layer 27 opening 70 housing 80 housing 71a, 71b, 71c filters 81a, 81b, 81c, 81d filters 82a, 82b, 82c, 82d outlet

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Katsuhiko Nakamae 4-12-5 Izumidai, Kita-ku, Kobe-shi, Hyogo

Claims (10)

[Claims] 1. A classifying filter for classifying a granular material, comprising a substrate having a plurality of holes formed therein, wherein a plane shape of an opening of each of the holes is a first length in a longitudinal direction and the longitudinal direction. A classification filter characterized by having an elongated shape having a second length in a short direction orthogonal to the filter. 2. The classification filter according to claim 1, wherein said substrate is made of a metal plate. 3. A second length in the lateral direction of each of the holes has a particle size of a granular material to be classified or a length in the vicinity thereof.
The classification filter according to claim 1. 4. The shape of the opening of each hole is rectangular.
The classification filter according to claim 1. 5. A first length in a longitudinal direction of an opening of the hole,
The classification filter according to claim 1, wherein the particulate matter that cannot pass through the opening has a length that allows the material to roll or move along the longitudinal direction of the opening. 6. The classification filter according to claim 1, wherein a ratio of the first length of the opening of the hole to the second length is 2 or more. 7. Each of the holes is regularly arranged in a substrate.
The classification filter according to claim 1. 8. The classification filter according to claim 1, wherein in the cross-sectional shape of each hole in the short direction, both surfaces or at least one surface of the substrate is wider than the narrowest portion. 9. The classification filter according to claim 1, for classifying polymer particles or inorganic particles. 10. A multi-stage filter comprising a combination of a plurality of classification filters according to claim 1.