WO2006004011A1

WO2006004011A1 - Filter and manufacturing method thereof

Info

Publication number: WO2006004011A1
Application number: PCT/JP2005/012116
Authority: WO
Inventors: Yoshimitsu Kankawa; Hiroshi Setowaki; Hiroshi Satomi; Hiroshi Kitou; Motoi Fukuda
Original assignee: Mold Research Co., Ltd.
Priority date: 2004-07-02
Filing date: 2005-06-30
Publication date: 2006-01-12
Also published as: JPWO2006004011A1; WO2006003703A1

Abstract

An integrated type sintered filter provided with a dense layer for an outer layer part and a porous inner layer part, and a method for manufacturing such filter at a high dimensional accuracy. The filter is provided for filtering a sample by permitting the sample to flow through a filtering part composed of a porous sintered body. In the filtering part, the parts other than inflow and outflow parts are covered with a high density sintered body. The sinter relative density of the porous sintered body is 50-90% and that of the high density sintered body is 95% or more. An interface between the porous sintered body and the high density sintered body is integrated by sintering.

Description

Specification

Filter and manufacturing method thereof

Technical field

[0001] The present invention relates to a sintered filter in which an outer layer portion has a dense ceramic or metal force and an inner layer portion also has a porous ceramic or metal force, and a manufacturing method thereof.

Background art

Conventionally, a ceramic or metal porous body has been used as a filter for performing filtration. In general, such a porous body is manufactured by using a ceramic or metal powder having a coarse particle size and sintering the pressed compact by a powder pressing method. However, since the manufactured sintered product is porous and fragile, it may be damaged when incorporated into a product such as a column, and it is necessary to prevent liquid leakage from the porous material. It is common to cover the outer periphery with another member. Therefore, ceramics and metal filters that use a porous sintered body are mainly those having an inner layer portion and an outer layer portion, and the inner layer portion is a ceramic, or is a filtration portion that is a metal porous body force. The outer layer portion is provided in close contact with the outer periphery of the filtration portion, and plays a role of preventing damage to the filtration portion and liquid leakage.

If a plastic material is used for the material of the outer layer, it may be damaged during use or may deteriorate with time, which increases the number of problems in use. In addition, when the liquid component that passes through the filtration part is a strong acid, strong alkali, or an organic solvent, the plastic material in the outer peripheral part is likely to deteriorate and liquid leakage is likely to occur.

[0003] For this reason, a technique is used in which the outer layer portion is made of a metal material and a porous body (inner layer portion) obtained by press molding is press-fitted. However, as the filter itself becomes thinner and its dimensions are reduced, It is difficult to manufacture products by press-fitting.

Further, in the above method, the porous property of the inner layer portion may be impaired by pressure, and since it is not integral molding, there is a risk of liquid leakage or separation between the inner layer portion and the outer layer portion being not completely adhered. .

[0004] On the other hand, in the case of a porous material having a ceramic material force, such a method as coating is used. Although there is a method of densifying the outer periphery of the product, if the product becomes smaller, the coating layer will penetrate into the interior, which may damage the filtration part, and a uniform outer layer part. Is difficult to form.

[0005] On the other hand, Patent Documents 1 to 3 disclose a method and an apparatus for manufacturing a sintered product in which metals or ceramic layers having different densities are adhered.

[0006] However, since the manufacturing method of Patent Document 1 cannot produce a plate-like laminated body and produce a force, the side wall of the porous sintered body is covered with a high-density sintered body to produce a filter. I can't. Even in the manufacturing method of Cited Document 2, since layers having different densities are laminated by pouring of slurry, it is impossible to form and force-manufacture layers by sequentially stacking layers. Therefore, it is difficult to manufacture a filter having a complex shape like a porous filter having a porous inner core, a high density outer peripheral force, and a filter having a branched shape. In addition, it is difficult to manufacture a product whose thickness varies in a desired shape in each layer.

The apparatus of cited document 3 is an apparatus for extrusion molding, and can only produce products having the same cross-sectional shape. Therefore, it is impossible to produce a product having a complicated shape with different cross-sectional shapes, and it is also impossible to change the thickness of each layer at an arbitrary place.

Patent Document 1: Japanese Patent Laid-Open No. 55-138007

Patent Document 2: JP 2001-278672 A

Patent Document 3: Japanese Patent Laid-Open No. 10-286812

Disclosure of the invention

Problems to be solved by the invention

[0007] The present invention has been made in consideration of the above-described problems in the prior art, and provides an integrated sintered filter in which the outer layer portion is a dense layer and the inner layer portion is porous. And a method for manufacturing the filter with high dimensional accuracy.

Means for solving the problem

[0008] The present invention is a filter for filtering a sample by circulating the sample through a filtering part having a porous sintered body force, and the filtering part covers a high-density sintered body except for the inflow and outflow part of the sample. The porous sintered body has a sintered relative density of 50 to 90%, and the high-density sintered body has The sintered relative density is 95% or more, and the interface between the porous sintered body and the high-density sintered body is integrated by sintering.

[0009] The filter according to the present invention has a filtration part that also has a porous sintered body strength, and the filtration part is covered with a high-density sintered body except for the sample inflow and outflow part. The porous sintered body of the inner layer part and the high-density sintered body of the outer layer part are integrated by sintering, so the parts with different densities are combined with each other by machining, The durability is very good because no peeling occurs at the interface between the inner layer and the outer layer. Since the sintered relative density of the porous sintered body is 50 to 90% and minute pores communicate with each other, the sample can be circulated for filtration. Since the high-density sintered compact is densified to a sintered relative density of 95% or higher, it does not have continuous pores and does not allow liquids to pass. Since the outer layer portion made of this high-density sintered body is in close contact with the filtration portion by sintering, liquid leakage due to the strength of the filtration portion is prevented.

The sintered relative density can be determined by the following equation.

Sintered relative density = (apparent density Z true density) X 100

[0010] Further, the present invention is a method for producing the above-described filter, wherein a molding material X for forming a high-density sintered body and a molding material Y for forming a porous sintered body are used with a two-color molding machine. Including the steps of injection molding, degreasing, and sintering to a desired shape, respectively, and the molding material X is 30 to 60 based on the total amount of the metal powder A and the material X having an average particle size of 20 / zm or less. It contains an organic binder in a volume% amount, and the molding material Y contains an organic binder in an amount of 30 to 60% by volume based on the total amount of metal powder B having an average particle size of 30 to LOO m and material Y. It is the method characterized by this.

[0011] By using molding powder X containing metal powder 層 having an average particle size of 20 μm or less and an organic binder in an amount of 30 to 60% by volume with respect to the total amount of material X, a high-density sintered body in the outer layer portion Can be formed. On the other hand, by using molding material Y containing 30 to 60% by volume of organic binder with respect to the total amount of metal powder の and material の having an average particle size of 30 to L 00 m, the inner layer is made porous. A sintered body can be formed. Molding materials X and Y are injection molded into a desired shape using a two-color molding machine, degreased, and sintered, so that the boundary surface between the inner layer and outer layer is integrated with the metal. Filter can be manufactured [0012] Further, the present invention is a method for producing the above-described filter, wherein a molding material X 'forming a high-density sintered body and a molding material Y' forming a porous sintered body are divided into two colors. It includes the steps of injection molding, degreasing, and sintering each into a desired shape using a molding machine, and the molding material X ′ contains ceramic powder C and material X having an average particle size of 0.5 / zm or less. 40% to 70% by volume of the organic binder, and the molding material Y ′ has an average particle diameter of 0.6 to: LO / zm of ceramic powder D and 40% of the total amount of the material Y. a method which is characterized by containing the organic binder 70 vol ^_0/0 amount.

[0013] By using the molding powder X 'containing 40 to 70 volume% of the organic binder with respect to the total amount of the ceramic powder C having an average particle size of 0.5 µm or less and the material X', the outer layer portion A high-density sintered body can be formed. On the other hand, by using molding material Y containing 40 to 70% by volume of organic binder with respect to the total amount of ceramic powder D and material Y having an average particle size of 0.6 to 10 m, the inner layer is made porous. A sintered body can be formed. By molding the molding materials X 'and Y' into a desired shape using a two-color molding machine, degreasing and sintering, the interface between the inner layer and outer layer is integrated by sintering. Ceramic filters can be manufactured.

[0014] By using a two-color molding machine, it is possible to easily and continuously form portions having different densities. That is, after one part is molded, another part in contact with that part is injection-molded, so that the concavity and convexity of both contact surfaces are completely coincident. Then, rather than sintering at a high temperature, the contact surfaces of both are welded. Therefore, the interface between them is completely integrated by the combination of unevenness and welding, and does not peel off. Further, by adjusting the mold structure of each layer, it is possible to obtain a filter having a complicated shape in which each layer has a desired shape. Accordingly, it is possible to manufacture a filter having a complicated shape and having an arbitrary thickness and an arbitrary shape in each layer as compared with the products obtained in the cited documents 1 to 3. According to this method, even a small sintered product of about 0.1 to Lmm can be manufactured with high dimensional accuracy, and the thickness of all or part of the porous sintered body can be reduced to 100. It can be as thin as m. Accordingly, even a filter having a thin portion having a thickness of 1 mm or less in the filtration portion can be stably supplied.

[0015] The sintered product according to the present invention is not limited to the method using a two-color molding machine. ひ (or the molding materials X ′ and Υ ′) were separately injection molded to obtain a molded product of X and a molded product of Ύ (or a molded product of X ′ and a molded product of Y ′). They can also be manufactured by combining them and then degreasing and sintering.

[0016] If the powders Α · Α (or powder C'D) are made of the same material, the sintering conditions can be adjusted more easily.

[0017] When the method for producing the metal filter is carried out, the powder A is mixed with the molding material Y (the blending amount is 90% by weight or less with respect to the total amount of the powder B), or When carrying out the method for manufacturing a ceramic filter, the powder C is added to the molding material Y ′ (the blending amount is 90% by weight or less with respect to the total amount of the powder D). It is possible to control the porosity. The porosity is calculated by the following formula.

Porosity = {1 (apparent density Z true density)} X 100

The true density is the density when the pores are assumed to be 0, and the apparent density is the density including the pores.

The invention's effect

[0018] As described above, the filter according to the present invention has a filter part made of a porous sintered body and an outer peripheral part made of a high-density sintered body. Since it is integrated by ligation, liquid leakage from the filtration part and separation of the boundary surface do not occur. In addition, according to the manufacturing method of the present invention, the filter can be manufactured without machining, so that the manufacturing process is simple and suitable for mass production of products having complex shapes. In addition, according to the manufacturing method according to the present invention, even a small filter can be manufactured with high dimensional accuracy, and a product in which the thickness of all or part of the filtration part is lmm or less is stable. Can be supplied.

Brief Description of Drawings

FIG. 1 is a view showing an example of a cylindrical filter according to the present invention.

FIG. 2 is a view showing an embodiment of a T-shaped filter according to the present invention.

Explanation of symbols

[0020] 1 Porous sintered body (filter part) 2 High density sintered body

BEST MODE FOR CARRYING OUT THE INVENTION

In the present specification, the interface between the porous sintered body and the high-density sintered body refers to a contact surface between the sintered bodies. Further, “integrated by sintering” means that the interface between the sintered bodies is welded by heating during sintering.

[0022] The filter part of the filter according to the present invention is a porous sintered body having a sintered relative density of 50 to 90%, and has continuous pores. The pore size depends on several factors such as the particle size of the powder to be used, the amount of organic binder added, and the sintering temperature. For example, using an alumina ceramic powder having an average particle size of 1 to 5 / ζ πι. When an organic binder is added in an amount of 40 to 60% by volume, heat degreasing is performed in the atmosphere, and sintering is performed at 1500 ° C, the average pore diameter of the continuous air holes is about 0.3 to 3 / ζ πι. The sintered relative density is 60-85%. Also, using stainless powder with an average particle size of 40-80 / ζ πι, an organic binder was added in an amount of 40-60 vol%, heat degreasing was performed with nitrogen, and sintering was performed at 1350 ° C in an argon atmosphere. In this case, the average pore diameter of the continuous vents is about 20-40 / zm, and the sintered relative density is 70-85%.

[0023] The sintered relative density of the porous sintered body (filter part) of the filter according to the present invention is more preferably 55 to 88%, and still more preferably 60 to 85%.

[0024] The filter according to the present invention can be manufactured by adjusting the sintering temperature in addition to the particle size of the powder used.

Specifically, molding materials X '' and Y '' are injection molded, degreased, and sintered into desired shapes using a two-color molding machine, respectively, or molding materials X '' and Y '' In the method of separately injection molding without using a two-color molding machine to obtain a molded body of X ′ ′ and a molded body of Y ′ ′, and then combining them for degreasing and sintering,

By setting the sintering temperature to a temperature at which the molding material X ′ ′ is densified to a sintering relative density of 95% or more and the sintering relative density of the molding material Y ′ ′ remains at 50 to 90%. A high-density sintered body and a porous sintered body coexist, and the interface between the parts can be integrated by sintering to produce a sintered product V.

[0025] When the sintered product according to the present invention is manufactured using the difference in densification temperature of each molding material, the difference in densification temperature between the above X ′ ′ and Y ′ ′ is 30 ° C. or more. Required, more preferably 50 ° C Above, more preferably 100 ° C or higher. In this specification, the densification temperature refers to a temperature at which the sintered relative density becomes 95% or more.

[0026] During the sintering step, the sintering temperature is adjusted to a temperature that is equal to or higher than the densification temperature of the molding material X ′ ′, and the sintered relative density of Y ′ ′ remains at 50 to 90%. The portion made of molding material X ′ ′ has a higher sintering relative density, while the portion made of molding material Y ′ ′ has a lower sintering relative density. Therefore, according to the method, it is possible to form a sintered body in which portions having different densities coexist without adjusting the difference in average particle diameter. Further, in the same manner as described above, the interface between the respective parts is integrated in the sintering process, so that a sintered product in which separation of the boundary surface does not occur can be manufactured.

[0027] As described above, by using the difference in the densification temperature in addition to the average particle diameter, a metal filter in which parts having different sintered relative densities coexist, and the interface between the parts is provided. However, an integrated filter can be obtained by sintering. According to this method, the metal filter according to the present invention can be manufactured even when the metal powder contained in each molding material is different.

Similarly, the filter according to the present invention can be manufactured even when the ceramic powder contained in each molding material is different.

Also, for products made of different materials with ceramics and metal power, by adjusting the sintering temperature and the sintering atmosphere, the filter has parts with different sintered relative densities. It is possible to create an integrated filter by sintering. For example, by using stainless steel or iron as the metal and alumina or zirconia as the ceramic, a filter having a portion having a metal force and a portion having a ceramic force can be manufactured.

[0028] A two-color molding machine refers to a machine capable of molding two types of materials into desired shapes. Generally, it has two screws and cylinder parts that are formed by fusing the material, and each mold force is filled in the mold at different timings at the desired position. A molding machine that can mold a desired shape.

[0029] In addition to the metal powder (or ceramic powder) and the organic binder, the molding material Y (or Υ ') has a high soft point resin (epoxy resin, urethane resin, polyester, etc.) as the third component. The porosity of the porous sintered body can be further increased by adding a terbium resin or a phenol resin.

[0030] Powders A and B may be a kind of metal powder or a mixed powder composed of two or more kinds of metal powders. The metal powder used in the production method of the present invention is a powder having a melting point of 600 ° C. or higher and can be sintered. Examples include carbonyl iron, carbonyl nickel, stainless steel, low alloy steel, titanium, titanium alloy, single or alloy powders of copper, silver, gold and the like, or a mixture thereof.

[0031] The average particle size of the metal powder A is more preferably 10 m or less. The average particle size of the metal powder B is more preferably about 50 m. When the powder particle size is increased, the powder is easily clogged between the screw and the cylinder at the time of injection molding, and molding becomes difficult, and a porous sintered body can be obtained by sintering at high temperature, but the strength decreases.

On the other hand, when manufacturing a ceramic filter, a finer powder than a metal powder is used because of its sintering characteristics. In the case of ceramics, the average particle diameter of powder C used to obtain a high-density sintered body is 0.5 m or less, and the average particle diameter of powder D used to obtain a porous sintered body Is preferably 4 μm or more.

[0033] Powders C and D may be a kind of ceramic powder or a mixed powder composed of two or more kinds of ceramic powder. Examples of ceramics used in the present invention include non-acidic ceramics such as alumina, zirconium oxide, ferrite, acidic titanium and barium titanate, non-acidic materials such as silicon carbide, silicon nitride, aluminum nitride and boron nitride. And ceramics, or a mixture thereof.

[0034] In the present invention, the same material strength as powder A means that when powder A is a single metal powder, powder B is also the same metal powder, and powder A is a mixed powder. In this case, the powder B is composed of the same metal powder as each metal powder constituting the powder A. The mixing ratio of each metal powder constituting powder A and the mixing ratio of each metal powder constituting powder B may be different, but are more preferably the same.

Similarly, the same material strength as powder C means that when powder C is a single ceramic powder, powder D is also the same ceramic powder, and when powder C is a mixed powder, powder D is , Composed of the same ceramic powder as each ceramic powder that constitutes powder C Let's do it! The mixing ratio of the ceramic powders composing the powder C and the mixing ratio of the ceramic powders composing the powder D may be different, but more preferably the same.

[0035] The molding material according to the present invention includes an organic binder of about 30 to about 60% by volume of the total amount of the molding material in the molding material (X and Y) of the sintered metal product. more preferred, that is contained preferably instrument about 3 5 to 50 volume ^_0/0. The molding material (X, Y) of sintered ceramics contains about 40 to about 60% by volume of organic binder, preferably about 40 to about 70% by volume of the total amount of molding material. More preferably. For the organic binder, thermoplastic resin, wax, plasticizer, lubricant and the like are used.

[0036] The thermoplastic resin has an effect of enhancing the retention after molding, and examples of the thermoplastic resin include polyethylene, polypropylene, polystyrene, acrylic resin, polyacetal, ethylene acetate butyl, polyvinyl butyral and the like. Can do.

[0037] Wax has the effect of facilitating fluidity during molding and thermal decomposition during degreasing. Examples of the wax include paraffin wax, carnauba wax, ester wax and the like.

[0038] The plasticizer has a function of lowering the temperature at the time of molding and a role of imparting flexibility, and examples of the plasticizer include phthalic compounds such as dioctyl phthalate and dibutyl phthalate.

[0039] The lubricant has a function of promoting fluidity during molding. Examples of lubricants include fatty acid ester compounds such as stearic acid, myristic acid and oleic acid.

[0040] In the production method of the present invention, "including degreasing and sintering steps" includes not only the case where the degreasing step 'sintering step is included separately but also the case where degreasing' sintering is performed in one step. Is also included.

[0041] The filter of the present invention can be used, for example, in a column for liquid chromatography, a filter for artificial dialysis, and the like. Further, if the production method of the present invention is used, not only a filter but also an oil-impregnated bearing, a degassing member, etc. can be produced as a porous product having a two-layer structure.

[0042] Next, an embodiment of a filter that is useful in the present invention will be described with reference to the drawings. The filter shown in Fig. 1 has a cylindrical shape with a diameter of 6 mm and a length of 20 mm. From the porous sintered body 1 with a diameter of 3 mm, It has the filtration part which becomes. The inflow part force is filtered by injecting the sample, allowing the sample to flow in the direction of the column axis, and collecting the filtrate coming out of the outflow part. The filter part is covered with the high-density sintered body 2 except for the sample inflow / outflow part, and the overall shape of the filter is along the columnar filter part (porous sintered body 1) and the peripheral wall of the filter part. It becomes a cylindrical shape consisting of two layers of the outer peripheral part (high-density sintered body 2) with a thickness of 1.5 mm.

The filter shown in Fig. 2 has a T-shaped branch shape with two cylinders vertically intersecting, and there are two outflow parts. The filter shown in Fig. 2 is capable of collecting a sample sample without interrupting filtration. Normally, the sample is circulated from the inflow part to the outflow part 1 with the outflow part 2 covered. When collecting the sample by filtration, remove the lid of the outflow part 2 to obtain the sample.

According to the manufacturing method of the present invention using a two-color molding machine, the filtration part and the outer peripheral part can be molded at the same time. Therefore, even if the filter has a complicated shape as shown in FIG. It can be integrally formed by a simple process.

[0043] Hereinafter, a method for producing the filter of the present invention will be described based on Examples.

Example 1

[0044] Manufacture of metal filters

The filter shown in FIG. 1 was produced by using a method that makes good use of the present invention.

Stainless steel powder (SUS316L) was used as the metal powder. Stainless steel powder with an average particle size of 6 / zm is used as the powder A used for the molding material X that forms the high-density sintered body. Stainless powder with a particle size of 50 μm was used.

As the organic binder, a mixture in which polyacetal, polypropylene, and paraffin wax were mixed at a ratio of 25:25:50 was used.

[0045] The composition of the molding material X and the molding material Y is as follows.

Molding material X: Powder A60 vol% + organic binder 40 vol ^_0/0

Molding material Y: Powder B65 volume% + organic binder 35 volume%

[0046] Injection molding was performed using a two-color molding machine. The molding temperature was set to 180 ° C, and a molded body consisting of a porous sintered body (filter part) in the center and a high-density sintered body in close contact with the outer periphery was produced. It was. The obtained green body was degreased at a maximum temperature of 400 ° C under a nitrogen atmosphere, and the degreased green body was sintered under an argon atmosphere at a maximum temperature of 1350 ° C '. The density of each part of the obtained sintered body was as follows, and the boundary surface between the high-density sintered body (outer peripheral part) and the porous sintered body (center part) was welded.

Sintered relative density High-density sintered body: 95%, porous sintered body: 85%

[0047] Among the manufactured filters, the high-density sintered body at the outer peripheral portion has fine independent pores of 5 μm or less, and the porous sintered body at the filtration portion has a pore diameter of about 20 to 30 m. It had continuous pores.

When an aqueous solution containing 5% ceramic powder of 100 m or less was actually passed through this filter, it was possible to capture powder having a particle size of 40 m or more without any problems such as liquid leakage.

[0048] From Example 1, a high-density sintered body (peripheral part) and a porous sintered body (filter part) coexist in the same product, and the interface between the high-density sintered body and the porous sintered body. A metal filter that was welded by sintering and had no problem in practical use could be obtained under the same sintering conditions without post-processing. Example 2

[0049] Manufacture of ceramics and metal power filters

The filter shown in Fig. 1 was manufactured using a molding material containing ceramic powder and a molding material containing metal powder.

[0050] The composition of each molding material is as follows.

Molding material of the outer peripheral portion: metal powder (stainless steel SUS304L powder: average particle diameter 10 mu m) 65 vol% + organic binder 35 vol ^_0/0

Molding material of the central portion (filtration unit): ceramic powder (alumina powder average particle size: 1.0 mu m) 55 volume ^_0/0 + organic binder 45 vol ^_0/0

The temperature at which the outer peripheral part (metal part) becomes dense is 1300 ° C, and the temperature at which the central part (ceramic part) becomes dense is 1550 ° C.

[0051] Injection molding was performed using a two-color molding machine. The molding temperature was set to 170 ° C, and a molded body comprising a filtration part and an outer peripheral part thereof was produced. The obtained molded body was degreased at a maximum temperature of 400 ° C. · nitrogen atmosphere, and the degreased molded body was sintered at a maximum temperature of 1350 ° C. under an argon atmosphere. The density of each part of the obtained sintered body was as follows, and the boundary surface between the high-density sintered body (outer peripheral part) and the porous sintered body (center part) was welded.

Sintered relative density High-density sintered body: 95%, porous sintered body: 90%

[0052] The high-density sintered body has fine independent pores, and the filtration part (porous sintered body) has continuous pores having a pore diameter of about 0.3 to 0.7 m. When an aqueous solution containing 5% of the following ceramic powder was passed through this filter, a powder having a particle size of 1.0 / zm or more that was free from defects such as liquid leakage could be captured.

According to Example 2, a high-density sintered body (peripheral part) and a porous sintered body (filter part) coexist in the same product, and the interface between the high-density sintered body and the porous sintered body is sintered. We succeeded in obtaining a welded metal / ceramic two-layer filter with no problems in actual use under the same sintering conditions without post-processing.

[0053] In this example, the sintering relative density was adjusted by adjusting the sintering temperature in addition to the powder particle size. In other words, if the sintering temperature is 1350 ° C, the ceramic part is not densified, and the sintered density can be kept lower. On the other hand, the metal part is densified at a temperature of 1300 ° C. Therefore, the metal part is densified under the above-mentioned sintering conditions. As a result, a sintered compact having a sintered relative density of 95% or more and a sintered relative density of 90% It was possible to obtain a filter coexisting with a porous sintered body.

[0054] In Examples 3 and 4 below, a method for producing a filter according to the present invention without using a two-color molding machine will be described.

Example 3

[0055] Manufacture of metal filters

The filter shown in FIG. 1 was manufactured using the following method.

Titanium powder was used as the metal powder. Titanium powder with an average particle size of 20 m is used as the powder for the molding material X that forms the high-density sintered body, and the average particle size is 50 / as the powder B that is used for the molding material Y that forms the porous sintered body. zm titanium powder was used. Further, in this example, in order to adjust the porosity of the porous sintered body, a molding material Y was prepared by mixing 20% by weight of powder A in addition to powder B.

Organic binders include polyacetal, polypropylene, and 《Raffin wax, 25: 2 A mixture mixed at a ratio of 5:50 was used.

[0056] The composition of the molding material X and the molding material Y is as follows.

Molding material X: Powder A60 vol% + organic binder 40 vol ^_0/0

Molding material Y: 65% by volume of powder (B + A) + 35% by volume of organic binder

[0057] Molding materials X and Y were respectively injection molded to produce an outer peripheral portion (high density sintered body) and a central portion (porous sintered body) shown in FIG. The molding temperature was 180 ° C. Insert the molded body Y (center) into the molded body X (outer peripheral part) and combine it. The combined molded body is degreased at the maximum temperature of 400 ° C 'argon atmosphere. 0 ° C · Sintered under high vacuum (10-3AB). The sintered relative density of the obtained sintered body was as follows, and the boundary surface between the high-density sintered body (outer peripheral portion) and the porous sintered body (filtered portion) was welded.

Sintered relative density High-density sintered body: 95%, porous sintered body: 84%

[0058] The high-density sintered body had fine independent pores, and the filtration part (porous sintered body) had continuous pores having a pore diameter of about 15 to 30 µm. When an aqueous solution containing 5% ceramic powder of 100 μm or less was actually passed through this filter, it was possible to capture powder having a particle size of 50 m or more with no problems such as liquid leakage.

From Example 3, a high-density sintered body (peripheral part) and a porous sintered body (filtering part) coexist in the same product, and the interface between the high-density sintered body and the porous sintered body is sintered. As a result, a metal filter with no problems in practical use was obtained under the same sintering conditions without post-processing. Example 4

[0059] Manufacture of sintered ceramics

The sintered product shown in FIG. 2 was manufactured using the following method.

Alumina powder was used as the ceramic powder. As powder C used for molding material X, which forms a high-density sintered body, alumina powder having an average particle size of 0.3 m is used as powder C, and as powder D used as molding material Y ′ that forms a porous sintered body, average grain is used. Alumina powder with a diameter of 7 m was used. Further, in this example, in order to adjust the porosity of the porous sintered body, in addition to powder D, 10% by weight of powder C of powder D was mixed to prepare molding material Y ′.

As the organic noda, a mixture in which acrylic resin, polypropylene, paraffin wax, dibutynophthalate and stearic acid were mixed at a ratio of 25: 25: 40: 5: 5 was used. [0060] The composition of the molding material X 'and the molding material Y' is as follows.

Molding material X ,; powder C55 vol% + organic binder 45 vol ^_0/0

Molding Y ,: powder (D + C) 60 vol% + organic binder 40 vol ^_0/0

[0061] Molding materials X 'and Y' were each injection-molded to produce the product shown in FIG. First, using molding material Y ', injection molding is performed using a mold that matches the shape of the filtration part (porous sintered body). Inserted into the mold to create the shape of the body. After that, injection molding is performed so that the molding material X ′ is filled outside the filtration part, and the obtained molded body is degreased and sintered, so that the inner part is porous and the outer part is sintered at high density. A filter with a binding power was manufactured.

The molding temperature was 180 ° C, and degreasing was performed at a maximum temperature of 400 ° 〇 · atmosphere. Sintering was performed at a maximum temperature of 1600 ° C in an air atmosphere.

The density of the obtained sintered body was as follows, and the boundary surface between the high-density sintered body (outer peripheral part) and the porous sintered body (filtered part) was welded.

Sintered relative density, high-density sintered body: 99%, porous sintered body: 85%

[0062] The high-density sintered body had fine independent pores, and the filtration part (porous sintered body) had continuous pores having a pore diameter of about 1 to 5 µm. When an aqueous solution containing 5% ceramic powder of 100 μm or less was actually passed through this filter, powder having a particle size of 8 m or more could be captured.

From Example 4, a high-density sintered body (peripheral part) and a porous sintered body (filtering part) coexist in the same product, and the interface between the high-density sintered body and the porous sintered body is sintered. We succeeded in obtaining a T-shaped ceramic filter that was welded and had no problem in actual use under the same sintering conditions and without post-processing.

[0063] [Comparative Example 1]

Manufacture of metal filters (comparative products)

A filter shown in FIG. 1 was prepared using metal powder having an average particle size of 10 m instead of metal powder B according to the present invention.

[0064] Stainless steel powder (SUS316L) was used as the metal powder. Stainless steel powder with an average particle diameter of 6 μm is used as the powder for the material forming the outer periphery, and the central part (filter part) is formed. Stainless steel powder with an average particle size of 10 m was used as the powder for the forming material.

[0065] The composition of each molding material is as follows.

Molding material of the outer peripheral portion: Stainless powder (6 μ m) 60 vol% + organic binder 40 vol ^_0/0 heart of molding material: stainless steel powder (10 m) 65 volume ^_0/0 + organic binder 35 vol ^_0/0 [ [0066] Injection molding was performed using a two-color molding machine. The molding temperature was 180 ° C, and the molded body shown in Fig. 1 was produced. The obtained compact was degreased at a maximum temperature of 400 ° C under a nitrogen atmosphere, and the degreased compact was sintered at a maximum temperature of 1350 ° C * argon atmosphere. The density of each part of the obtained sintered body was as follows, and the boundary surface between the central part and the outer peripheral part was welded.

Sintering relative density Outer part: 95%, Center part: 94%

[0067] In Comparative Example 1, although the boundary surface between the central portion and the outer peripheral portion was welded, the sintered relative density of the central portion, which was intended to be a porous sintered body, was as high as 94%, and the continuous pores The sample could not be circulated without having a filter, so it did not function as a filter.

[0068] [Comparative Example 2]

Ceramics' J: Watching for products (t &)

A filter shown in FIG. 1 was prepared using ceramic powder having an average particle size of 5 μm instead of ceramic powder C which is useful in the present invention.

[0069] Alumina powder was used as the ceramic powder. Alumina powder with an average particle size of 5 m was used as the powder for the material forming the outer peripheral portion, and alumina powder with an average particle size of 7 m was used as the powder for the material for forming the central portion (filter part).

Further, in this example, in order to adjust the porosity of the central portion, a molding material for forming the central portion by mixing alumina powder having an average particle size of 5 m in addition to alumina powder having an average particle size of 7 m. Was prepared.

As the organic noda, a mixture in which acrylic resin, polypropylene, paraffin wax, dibutynophthalate and stearic acid were mixed at a ratio of 25: 25: 40: 5: 5 was used.

[0070] The composition of each molding material is as follows.

Molding material on the outer periphery: Alumina powder (average particle size 5 μm) 55% by volume + 45 organic binders Product ⁰ / o

Molding material of the central portion: alumina powder (average particle diameter 7 mu m + an average particle diameter of 5 mu m) 60 volume ^_0/0 + organic binder 40 vol ^_0/0

[0071] Each molding material was injection-molded to produce a molded body shown in FIG. The molding temperature was 180 ° C. The molded body at the center part was inserted into the molded body at the outer peripheral part and combined, and an acrylic resin was diluted with a solvent at the insertion part. The combined molded body was degreased at a maximum temperature of 400 ° C in an air atmosphere, and the degreased molded body was sintered at a maximum temperature of 1200 ° O · atmosphere. The density of the obtained sintered body was as follows, and the boundary surface between the central portion and the outer peripheral portion was welded.

Sintering relative density Outer part: 89%, Center part: 85%

[0072] In Comparative Example 2, although the boundary surface between the central portion and the outer peripheral portion was welded, continuous pores were also generated in the outer peripheral portion, and the sample that flowed to the central portion leaked, and a desired filter could be obtained. could not.

Claims

The scope of the claims

[1] Porous sintered body strength is a filter for filtering a sample by circulating the sample through a filtration section.

The filtration part is covered with a high-density sintered body other than the inflow / outflow part of the sample,

The sintered relative density of the porous sintered body is 50 to 90%,

The high-density sintered body has a sintered relative density of 95% or more,

A filter characterized in that an interface between the porous sintered body and the high-density sintered body is integrated by sintering.

[2] A method of manufacturing a filter according to claim 1,

A molding material X for forming a high-density sintered body and a molding material Y for forming a porous sintered body are each formed by injection molding into a desired shape, degreasing, and sintering using a two-color molding machine. And

The molding material X contains metal powder A having an average particle size of 20 m or less, and an organic binder in an amount of 30 to 60% by volume based on the total amount of the material X,

The molding material Y contains a metal powder B having an average particle size of 30 to: LOO / zm, and an organic binder in an amount of 30 to 60% by volume based on the total amount of the material Y.

[3] A method of manufacturing a filter according to claim 1,

Includes the process of degreasing and sintering the molding material X forming the high-density sintered body and the molding material Y forming the porous sintered body by combining the moldings X and Y obtained by injection molding, respectively. And

[4] The method according to claim 2 or 3, wherein the powder A and the powder B have the same material force.

[5] The method according to any one of claims 2 to 4, wherein the molding material Y further contains the powder A in an amount of 90% by weight or less based on the total amount of the powder B.

[6] A method for producing a filter according to claim 1, The process of injection molding, degreasing, and sintering the molding material X 'forming a high-density sintered body and the molding material Y' forming a porous sintered body into a desired shape using a two-color molding machine. Including, and

The molding material X ′ contains 40% to 70% by volume of an organic binder with respect to the total amount of the ceramic powder C having an average particle size of 0.5 / z m or less and the material X.

The molding material Y contains a ceramic powder D having an average particle size of 0.6 to 10 m and an organic binder in an amount of 40 to 70% by volume based on the total amount of the material Y.

[7] A method of manufacturing a filter according to claim 1,

The molding material X ′ forming the high-density sintered body and the molding material Y ′ forming the porous sintered body are combined with the moldings X ′ and Y ′ obtained by injection molding, and then degreased and sintered. Including the steps of:

[8] The method according to claim 6 or 7, wherein the powder C and the powder D are made of the same material.

[9] The method according to any one of claims 6 to 8, wherein the molding material Y ′ further contains the powder C in an amount of 90% by weight or less based on the total amount of the powder D.