JPWO2008136236A1 - Clad filter material and method for producing the clad filter material - Google Patents

Abstract

To provide a clad filter material that can be applied to fields where conventional porous bodies have been used, can control the permeation rate of gas and liquid, and can be miniaturized, and a method for producing the clad filter material. Objective. In order to achieve this object, it is a plate-like filter material that can transmit gas or liquid from one surface side to the other surface side, and a porous metal layer is bonded to one or both sides of a felt-like fiber layer. Adopt clad filter material which is a composite multilayer material. Moreover, the manufacturing method of the clad filter material which laminates a felt-like fiber layer and a porous metal layer and carries out thermocompression bonding is employ | adopted.

Description

  The present invention relates to a clad filter material in which a porous metal layer and a felt-like fiber layer are bonded together and a method for producing the same.

  The porous body is characterized by its porosity, large surface area, surface characteristics, permeability, etc. because it is porous, and is used in various fields such as separation membranes, adsorbents, catalysts, and battery members. Examples of the porous body include polymer porous bodies such as porous carbon, foam metal, plated nonwoven fabric, electroformed material, expanded metal, and polyvinyl formal. For example, Patent Document 1 discloses a catalyst base material in which a net and an inorganic fiber are made composite porous as a catalyst base material suitable for a flue gas denitration catalyst. In addition, a porous body has attracted attention as a battery member, and is used as a permeable membrane for a direct methanol fuel cell.

  Here, in the direct methanol fuel cell, hydrogen ions decomposed from methanol, which is a liquid fuel, are permeated through the electrolyte membrane. However, there are cases where output voltage drops and fuel loss may occur due to the crossover phenomenon in which methanol passes through the electrolyte membrane without being decomposed, reaches the air electrode, and reacts with oxygen. ing. For example, Patent Document 2 discloses a proton-conductive polymer membrane having methanol blocking properties, which relates to a membrane-electrode assembly as a constituent material of a solid polymer fuel cell, a direct liquid fuel cell, and a direct methanol fuel cell. And a membrane-electrode assembly having a sufficient bonding strength while reducing methanol crossover.

JP 2007-90319 A JP 2006-278193 A

  In the above prior art, a technique for controlling the permeation rate of a substance to a desired state has been desired. Therefore, the present invention is applicable to a field where a conventional porous body has been used, and it is possible to control a gas and liquid permeation rate, and to make a clad filter material that can be miniaturized and a method for producing the clad filter material. The purpose is to provide.

  As a result of intensive studies, the present inventors have achieved the above object by adopting the following clad filter material and a method for producing the clad filter material.

Clad filter material: The clad filter material according to the present invention is a plate-shaped filter material that can transmit gas or liquid from one surface side to the other surface side, and the filter material is made of a felt-like fiber layer. It is a composite multilayer material in which a porous metal layer is bonded to one side or both sides.

  In the clad filter material according to the present invention, the porous metal layer preferably uses a perforated metal foil.

  In the clad filter material according to the present invention, the porous metal layer preferably uses a porous sponge-like metal sheet material.

  In the clad filter material according to the present invention, the porous metal layer is made of copper, copper alloy, titanium, titanium alloy, tantalum, tantalum alloy, niobium, niobium alloy, nickel, nickel alloy, vanadium, platinum, palladium, heat-resistant aluminum, stainless steel. Those made of any material of steel are preferred.

  In the clad filter material according to the present invention, the porous metal layer preferably has a thickness of 1 μm to 500 μm.

  In the clad filter material according to the present invention, the felt-like fiber layer is preferably a metal nonwoven fabric made of metal fibers.

  In the clad filter material according to the present invention, the felt-like fiber layer is preferably a resin nonwoven fabric made of resin fibers.

  In the clad filter material according to the present invention, the resin fiber is preferably a self-bonding nonwoven fabric.

  In the clad filter material according to the present invention, the felt-like fiber layer uses a catalyst-carrying fiber carrying a platinum-based catalyst component, a palladium-based catalyst component, a gold-based catalyst component, or an iron-based catalyst component on the fiber surface. Those using a catalyst-supporting nonwoven fabric obtained by combining one or more of these are preferred.

  In the clad filter material according to the present invention, the felt-like fiber layer preferably uses a nonwoven fabric made of a composite fiber in which two or more of the resin fiber, the catalyst-carrying fiber, and the metal fiber are combined.

Manufacturing method of clad filter material: The manufacturing method of the clad filter material according to the present invention is a manufacturing method of the above clad filter material, characterized in that the clad filter material is obtained through the following steps A and B.
Step A: A perforated metal foil or a porous sponge-like metal sheet constituting the porous metal layer is brought into contact with one or both sides of the felt-like fiber layer to form a laminated state.
Step B: While maintaining the lamination state, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered to bond the felt-like fiber layer and the porous metal layer. A clad filter material is obtained.

The manufacturing method of the clad filter material which concerns on this invention is a manufacturing method of the said clad filter material, Comprising: It becomes a clad filter material through the following process a-process c, It is characterized by the above-mentioned.
Step a: Using one or more of resin fibers, catalyst-supporting fibers, and metal fibers for constituting the felt-like fiber layer, selection or blending of raw material fibers for constituting the felt-like fiber layer And adjust the raw fiber.
Step b: Raw material constituting the felt-like fiber layer in accordance with the layer structure (porous metal layer / felt-like fiber layer or porous metal layer / felt-like fiber layer / porous metal layer) of the clad filter material to be manufactured The fibers are brought into contact with a perforated metal foil or a sponge-like metal sheet material constituting the porous metal layer to form a laminated state.
Step c: While maintaining the laminated state obtained in the step b, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered, so that the felt-like fiber layer and the porous layer are porous. A clad filter material in which a metal layer is bonded is obtained.

  The clad filter material according to the present invention has a structure in which a felt-like fiber layer and a porous metal layer are laminated, so that gas or liquid sequentially passes through layers having different transmission speeds. In comparison, the transmission speed can be easily controlled to an arbitrary state. That is, the porous metal layer can be easily designed in a porous shape, and the felt-like fiber layer can arbitrarily adjust the fiber packing density, so that the permeation rate of gas or liquid can be controlled with high accuracy. Moreover, since the felt-like fiber layer has a large specific surface area, a contact area with a gas or a liquid can be secured. Therefore, the clad filter material according to the present invention can be provided as a clad filter material whose transmission rate can be controlled, whose surface shape is stable, and excellent in heat resistance. Further, according to the method for producing a clad filter material of the present invention, while maintaining the laminated state of the felt-like fiber layer and the porous metal layer, the press pressure is maintained while the surface of the felt-like fiber layer is softened by heating. Since the felt-like fiber layer and the porous metal layer are bonded together by the heat treatment, the gap between the fibers of the felt-like fiber layer is caused by heat in the hole portion of the porous metal layer where the felt-like fiber layer and the porous metal layer are not in contact with each other. It can be manufactured by a simple method while maintaining the permeability of gas or liquid without melting.

  Hereinafter, the best embodiment of the clad filter material according to the present invention and the method for producing the clad filter material will be described.

Clad filter material: The clad filter material according to the present invention is a plate-like filter material that allows gas or liquid to pass from one surface side to the other surface side, and the filter material is a felt-like fiber layer. It is a composite multilayer material in which a porous metal layer is bonded to one side or both sides.

  It is preferable to use a perforated metal foil for the porous metal layer. The perforated metal foil refers to a metal foil having an opening penetrating in the thickness direction in an arbitrary shape and opening ratio. The shape of the opening can be formed according to the application, such as a circle, an ellipse, or a slit. The perforated metal foil is excellent in pattern formation accuracy such as the position, shape, number, and aperture ratio of the opening, so it can be designed with high accuracy and excellent adaptability to conditions such as a permeating gas or liquid and a desired permeation speed. Yes. For example, as shown in FIGS. 2A to 2E, the opening pattern of the perforated metal foil causes the openings to be unevenly distributed even when the pitch of the openings is equal (FIGS. 2A and 2B). ((C), (d)) is also possible, the opening area of each hole is made uniform ((a), (c)), or the opening area and shape of the hole are non-uniform ((b) , (D), (e)). Furthermore, it is suitable for reducing the thickness of the porous metal layer. Therefore, the transmission speed can be accurately controlled while being thin.

  The opening shape of the perforated metal foil can be selected in accordance with the application, but the opening diameter (maximum width of the opening) is preferably 0.1 μm to 100 μm as the size capable of maintaining the opening shape.

  Moreover, the aperture ratio of the perforated metal foil can be appropriately set according to the application. However, considering the strength that can maintain the shape of the perforated metal foil, the maximum aperture ratio is considered to be about 60%. The lower limit of the aperture ratio is not particularly limited as long as the desired substance can be transmitted.

  The perforated metal foil can be manufactured using a method such as punching, laser drilling, printing, dry thin film formation, etching, liquid resist method and the like. Considering the workability and work efficiency, when the number of openings is small, it is preferable to manufacture by laser drilling. An etching method is suitable when an opening having an opening width of about 15 μm to 100 μm is formed. In addition, when forming the opening shape of a fine through-hole in a taper shape, if it etches from the single side | surface side of metal foil, a taper-shaped opening shape can be formed easily. Moreover, after forming the through-hole of about 10 micrometers, the opening diameter can also be made small to about 1 micrometer-8 micrometers by the plating process. And, when processing a fine opening shape with an opening width of 50 μm or less, if manufactured by the resist method shown below, the degree of freedom in shape design can be increased, and a wide range of design conditions such as shape and size can be handled, In addition, fine pores can be formed beautifully and can be economically manufactured with a wide range of materials.

  A method for producing a perforated metal foil using a resist method should first have a thickness using a printing method such as a screen printing method, a gravure printing method, a relief printing method, an intaglio printing method, or a photoresist. Corresponding to the shape of the hole portion of the perforated metal foil, an etching resist layer serving as a mold is formed on the surface of the supporting metal. In a state where the etching resist layer is formed on the surface of the supporting metal, the metal plating layer is electrodeposited on a portion other than the etching resist layer serving as a mold by electrolytic plating. Subsequently, the perforated metal foil is obtained by removing the etching resist layer and peeling the supporting metal. The perforated metal foil thus obtained can have a thickness capable of adjusting the permeation rate as a porous metal layer according to the present invention, which is thinner than the thickness of a sponge-like metal sheet material described later. .

  In addition to the perforated metal foil, it is also preferable to use a porous sponge-like metal sheet material for the porous metal layer. Sponge-like metal sheet material refers to so-called foam metal, and has a porous shape and a large surface area, so that gas or liquid can be dispersed in the porous metal layer, and the contact area between the gas or liquid and the porous metal layer is wide. Become. Further, unlike the case of the perforated metal foil in which one hole penetrates in the thickness direction, the permeation path of the porous metal layer becomes long. For this reason, the permeation | transmission pressure of the gas or liquid which permeate | transmits a sponge-like metal sheet material can be reduced. Therefore, when the sponge-like metal sheet material is pasted on the felt-like fiber layer as a porous metal layer, the sponge-like metal sheet material becomes a buffer material when the gas or liquid flows in or out from the cladding filter material, and the gas flowing in at high pressure Alternatively, the liquid can be permeated under reduced pressure, and the amount of material flow can be controlled.

  The porous metal layer is made of any material of copper, copper alloy, titanium, titanium alloy, tantalum, tantalum alloy, niobium, niobium alloy, nickel, nickel alloy, vanadium, platinum, palladium, heat-resistant aluminum, and stainless steel. Is preferable, and can be selected according to the application of the clad filter material. For example, when the clad filter material itself according to the present invention is used as a reaction catalyst, it is preferable to use vanadium, platinum, or palladium according to the catalytic reaction.

  Depending on the combination of the porous metal layer and the felt-like fiber layer, there are cases where there are many voids on the bonding surfaces of both layers, and sufficient adhesion cannot be obtained. In this case, the adhesion strength can be increased by roughening the surface of the porous metal layer. What is necessary is just to perform the roughening process of a porous metal layer to the adhesion surface side with a felt-like fiber layer at least.

  For the roughening treatment of the porous metal layer, a method of roughening the surface by etching or performing plating treatment can be employed. However, since the porous metal layer is a thin and fine porous metal, it is preferable to employ a plating process because it is easy to uniformly perform the roughening process on the surface on the bonding surface side.

The roughening treatment by plating most commonly employs a method of depositing fine metal particles on the surface of the porous metal layer and then performing covering plating in order to prevent the fine metal particles from falling off. That is, the formation of fine metal particles attached to the surface of the porous metal layer is performed by cathodic polarization of the porous metal layer itself and adopting the condition of burnt plating. The burn plating conditions are not particularly limited, and are determined in consideration of the characteristics of the production line. For example, if fine copper particles are formed by copper plating using a copper sulfate-based solution, the concentration is 5 g / L to 20 g / L copper, 50 g / L to 200 g / L sulfuric acid, and other additives as necessary. (Α-naphthoquinoline, dextrin, glue, thiourea, etc.), liquid temperature 15 ° C. to 40 ° C., current density 10 A / dm ^{2 to} 50 A / dm ² , and the like.

Then, as the covering plating for preventing the fine metal particles from falling off, the fine metal particles are uniformly deposited so as to cover the fine metal particles under smooth plating conditions in order to prevent the fine metal particles deposited and adhered from falling off. Therefore, a high concentration electrolyte is used compared to the case where fine metal particles are deposited. The smooth plating conditions are not particularly limited and are determined in consideration of the characteristics of the production line. For example, in the case of copper plating using a copper sulfate-based solution, the concentrations are copper 50 g / L to 80 g / L, sulfuric acid 50 g / L to 150 g / L, liquid temperature 40 ° C. to 50 ° C., current density 10 A / dm ² to 50 A. / Dm ² and so on.

  In the clad filter material according to the present invention, the porous metal layer may be eroded along with the permeation of gas or liquid. Therefore, the porous metal layer is preferably subjected to surface treatment to improve the corrosion resistance in consideration of the relationship between the constituent material of the porous metal layer and the permeate. Therefore, the outermost layer of the perforated metal layer has an organic rust prevention treatment using imidazole and triazole agents, zinc alloys such as zinc and brass, nickel alloys, chrome plating for the purpose of ensuring long-term storage. It is also possible to perform an inorganic rust prevention treatment using a composition such as chromate. For example, when the clad filter material according to the present invention is used for a fuel permeable membrane of a direct methanol fuel cell, a tin-nickel alloy plating film is formed on the surface of the porous metal layer. Corrosion resistance can be improved.

  In addition, the perforated metal layer can use the thing which gave the roughening process and the antirust process arbitrarily to the adhesion surface with a felt-like fiber layer. That is, the concept includes a case where the roughening treatment is performed alone, the case where only the rust prevention treatment is performed without performing the roughening treatment, and the case where both the roughening treatment and the rust prevention treatment are performed.

  Moreover, it is preferable that the thickness of a porous metal layer is 1 micrometer-500 micrometers. The thickness of the porous metal layer can be arbitrarily set within the above range depending on the use of the cladding filter material, the permeation rate of gas or liquid, and the like. When the thickness of the porous metal layer is less than 1 μm in the case of a perforated metal foil, the strength is insufficient, and in the case of a sponge-like metal sheet material, the permeability is likely to be uneven and the inflowing gas or liquid Therefore, it is difficult to adjust the permeation speed in every application. On the other hand, a porous metal layer having a thickness exceeding 500 μm does not need to improve the strength as a clad filter material even if it exceeds this thickness, and is not suitable for practical use in terms of reduction in size and weight. The more preferable thickness of the porous metal layer is 3 μm to 30 μm when a perforated metal foil is used, and is 50 μm or more when a sponge-like metal sheet material is used.

  In addition, the clad filter material using the porous metal layer made of a spongy metal sheet material having a thickness of 50 μm or more can not only prevent methanol crossover, but is also used for a methanol permeable membrane of a direct methanol fuel cell. In this case, the degassing performance of carbon dioxide generated by the decomposition of methanol is improved.

  Next, fibers or nonwoven fabrics that can be used for the felt-like fiber layer will be described. The felt-like fiber layer used in the present invention is preferably a non-woven fabric which is deposited in a state where a plurality of fibers are used as constituent materials and these are irregularly mixed. When such a nonwoven fabric fiber layer is provided, not only can a gas or liquid flow path be secured, but also a liquid can be retained with a wide contact area with the gas or liquid, and every corner by capillary force. Liquid can penetrate.

  For the felt-like fiber layer, a metal nonwoven fabric obtained by pressing metal fibers can be used. For example, metal wool etc. are mentioned. When a metal nonwoven fabric is used, a felt-like fiber layer excellent in heat resistance and durability can be obtained, and a clad filter material using a metal nonwoven fabric as a felt-like fiber layer is a flue gas denitration catalyst member for passenger cars, It is suitable as an exhaust gas deodorization catalyst member and a combustion catalyst member.

  Moreover, the said felt-like fiber layer can use the resin-made nonwoven fabrics which consist of a resin fiber. Examples of the resin fiber forming the resin nonwoven fabric include rayon fiber, cellulose fiber, cross-linked polyvinyl alcohol fiber, liquid crystal polymer, and polyester. In particular, a self-bonding nonwoven fabric using a polyester or a liquid crystal polymer is preferable because sufficient adhesive strength between fibers can be obtained without using a binder. In other words, the self-bonding nonwoven fabric has a high melting point and inevitably increases the softening temperature of the surface, so it is suitable for thermocompression bonding at high temperatures and has sufficient adhesive strength with the porous metal layer without using a binder. Is preferable, and the fiber layer can be maintained. Conventionally, epoxy and acrylic resins are generally used as the binder when the resin fiber layer and the metal layer are bonded together, but such a self-fusing resin is used as the binder for the clad filter material. When methanol is used, the problem is that the binder component is eluted in methanol. However, by employing a self-bonding nonwoven fabric, the above-described binder is not required, and the binder component does not elute into methanol.

  Further, the felt-like fiber layer is a catalyst-carrying fiber carrying one of a platinum-based catalyst component, a palladium-based catalyst component, a gold-based catalyst component, and an iron-based catalyst component on the fiber surface. A catalyst-supporting nonwoven fabric used in combination of the above can be used. Since the cladding filter material according to the present invention can control the permeation rate of gas or liquid, when a felt-like fiber layer made of a catalyst-supporting nonwoven fabric is used, the gas or liquid is retained in the felt-like fiber layer. Thus, the catalytic action of the catalyst-supporting fiber can be effectively exhibited. Cladding filter material using a felt-like resin layer made of a catalyst-supporting non-woven fabric is miniaturized as, for example, a permeable membrane that can produce a fuel reforming effect, a flue gas denitration catalyst member such as a passenger car, an exhaust gas deodorization catalyst member, or a combustion catalyst member , High functionality can be achieved.

  And the felt-like fiber layer can use the nonwoven fabric made from a composite fiber which combined 2 or more types of resin fiber, catalyst carrying | support fiber, and metal fiber. For example, when metal fibers are included in the felt-like fiber layer, resin fibers can be combined to adjust the basis weight of the felt-like fiber layer, or to take into account the corrosion resistance, adjustment of the catalyst amount, and the like.

  The clad filter material has a configuration in which a perforated metal foil or a sponge-like metal sheet material is bonded to only one side of the felt-like fiber layer, depending on the application, and a perforated metal foil or sponge-like on both sides of the felt-like fiber layer. Any of a configuration in which a metal sheet material is laminated, a configuration in which a perforated metal foil is laminated on one surface of a felt-like fiber layer, and a sponge-like metal sheet material is laminated on the other surface may be used.

  Moreover, when bonding a porous metal layer on both surfaces, the aperture ratio (porosity), thickness, etc. of each surface can be set individually. When the perforated metal foil is bonded to both sides of the felt-like fiber layer, the position, size and shape of the perforated metal foil bonded to each surface can be arbitrarily set. By changing the position and size of the holes of each perforated metal foil provided on both sides of the felt-like fiber layer, the transmission speed can be finely adjusted. In addition, an arbitrary pattern can be formed as necessary, for example, when gas such as carbon dioxide is easily removed or when the gas is retained.

  In addition, the felt-like fiber layer and / or the porous metal layer may be subjected to a surface modification treatment such as a hydrophilic treatment, introduction of a polar group, or a physical roughening treatment. By such surface modification treatment, for example, catalyst supportability, water retention, and adhesion between the felt-like fiber layer and the porous metal layer can be improved. Examples of the surface modification treatment include grafting treatment, sulfonation treatment, plasma treatment, UV treatment, chemical treatment, surface mechanical polishing, and the like. In addition, the porous metal layer may be subjected to a surface treatment such as a chromate treatment according to the purpose.

  Moreover, a roughening process can be given to the surface of the perforated metal foil in a contact surface with a felt-like fiber layer, and hydrophilicity can be provided. By imparting hydrophilicity to the surface of the perforated metal foil, the liquid easily spreads to the vicinity of the contact surface with the felt-like fiber layer. For example, when a clad filter material is used as an adjustment filter for the fuel supply amount of a direct mail type fuel cell, the fuel can reach every corner of the clad filter material to achieve uniform fuel retention. The output characteristics can be improved.

  And it is preferable that the thickness of the clad filter material which concerns on this invention is 25 micrometers-600 micrometers. Considering the strength of the clad filter material, the lower limit of the thickness is 25 μm. The clad filter material according to the present invention is characterized by being capable of controlling the transmission speed while being thin and light, and therefore, the clad filter material exceeding 600 μm is difficult to solve the problem of downsizing. When a carbonaceous porous material is used as a filter material, it is difficult to reduce the thickness due to strength problems, but the clad filter material according to the present invention is characterized in that it can be thinned with sufficient strength. is there.

Manufacturing method of clad filter material: A first manufacturing mode and a second manufacturing mode of the clad filter material according to the present invention are shown in order.

[First production form of clad filter material]
The 1st manufacturing form of the clad filter material which concerns on this invention makes it the said clad filter material through the following processes A and B. FIG. 1 is a schematic view showing a process of attaching the porous metal layer 3 to both sides of the felt-like fiber layer 2 and will be described with reference to this figure.

Step A: A perforated metal foil or a porous sponge-like metal sheet constituting the porous metal layer is brought into contact with one surface or both surfaces of the previously formed felt-like fiber layer to form a laminated state. For example, the release film 6, the porous metal layer 3, the felt-like fiber layer 2, and the porous metal layer 3 are laminated on the press plate 5 in this order (see FIGS. 1 (1) to (3)).

  The release film 6 is used to prevent the press plate 5 and the porous metal foil 3 from being bonded to each other by press pressing and to improve the finish after peeling. In addition, when a copper foil (not shown) is sandwiched between the press plate 5 and the release film 6 as a pressing process aid during pressing, the effect of excellent thermal conductivity is exhibited, so that the press processing finish is good. It is preferable.

Step B: While maintaining this laminated state, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered to bond the felt-like fiber layer and the porous metal layer together. A clad filter material is obtained. The softening temperature of the felt-like fiber layer surface refers to a temperature at which the components of the felt-like fiber layer begin to soften and deformation of the surface of the felt-like fiber layer starts at least without applying physical force.

  For example, as shown in FIG. 1 (3), a release film 6 and a press plate (end plate, stainless steel plate, etc.) 5 are further placed in this order on the top surface of the laminate of the constituent materials. As shown to 4), it mounts on the press machine 4 and applies a press pressure. At this time, in order to facilitate the joining of the felt-like fiber layer and the porous metal layer, a press pressure is applied in a state where the surface of the felt-like fiber layer is softened by heating to enhance the adhesion with the porous metal layer. For example, when the porous metal layer 3 is provided on both sides, the press pressure is applied in a state where the upper and lower press plates 5 and 5 are heated to a desired temperature. Thereby, a felt-like fiber layer and a porous metal layer are thermocompression bonded. Then, by lowering the temperature thereafter, as shown in FIG. 1 (5), the clad filter material 1 in which the felt-like fiber layer 2 and the porous metal layer 3 are bonded together is obtained.

Although the press pressure in the process B varies depending on the type of the laminated material, in order to obtain a state in which the contact surface portion between the porous metal layer and the felt resin layer is thermocompression bonded and the fiber of the felt resin is maintained. applying a pressure in the range of ^{1kg / cm 2 ~60kg / cm 2} . More preferably, a pressure of about 10 kg / cm ² is applied.

  As described above, the heating temperature at the time of pressurization needs to be equal to or higher than the softening temperature of the surface of the felt-like fiber layer, but the softening temperature of the felt-like fiber layer is a constituent component of the felt-like fiber layer, the fiber diameter. It depends on various conditions such as the density of the nonwoven fabric. Accordingly, the heating temperature is 5 to 15 ° C higher than the softening point of the felt-like fiber layer surface, preferably 5 to 10 ° C higher, depending on the material, pressure, humidity, atmosphere (air, vacuum) time, etc. It is preferable to set appropriately within the range. By setting the heating temperature in the above range, only the heated surface of the felt-like fiber layer is melted, so that the fiber layer is maintained and fused to the porous metal layer. Moreover, the felt-like fiber layer can be prevented from oozing out into the opening.

  At this time, when heating from the porous metal layer side using the thermal conductivity of the metal, both layers are joined at the contact portion between the porous metal layer and the felt-like fiber layer, whereas the opening portion of the porous metal layer is The felt-like fiber layer does not melt because the metal is not in contact with the felt-like fiber layer, so that the permeability of the felt-like fiber layer at the opening is ensured. The heating time is preferably about 10 seconds to 5 minutes so that only the vicinity of the contact surface between the felt fiber layer and the porous metal layer is thermocompression bonded.

  Here, unlike the above method, when the metal layer and the felt-like fiber layer are joined together and then a method of providing an opening in the metal layer with a laser or the like is used, the felt-like fiber layer in the opening portion of the metal layer is melted by heating. However, the melted state of the felt-like fiber layer at the opening tends to vary, and the accuracy of the permeation performance is poor.

[Second production form of clad filter material]
The 2nd manufacturing form of the clad filter material which concerns on this invention is made into a clad filter material through the following process a-process c.

Step a: Selection or blending of raw fibers for constituting a felt-like fiber layer using any one or more of resin fibers, catalyst-supporting resin fibers, and metal fibers for constituting a felt-like fiber layer The raw fiber is adjusted. The raw fiber is selected according to the use of the clad filter material. Thus, if it adjusts from a raw material fiber, the felt-like fiber layer optimal for use conditions can be formed. In addition, as in the first production mode, compared to the case where the fiber layer is formed in advance, press forming is only required once, so that not only the process can be simplified but also the influence of heating on the felt-like fiber layer can be reduced. .

Step b: Raw material constituting the felt-like fiber layer in accordance with the layer structure (porous metal layer / felt-like fiber layer or porous metal layer / felt-like fiber layer / porous metal layer) of the clad filter material to be manufactured The fibers are brought into contact with a perforated metal foil or a sponge-like metal sheet material constituting the porous metal layer to form a laminated state. At this time, it is preferable to prepare a mold and laminate the constituent materials of the clad filter material in the mold because the shape stability during pressing is improved.

Step c: While maintaining the laminated state obtained in step b, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered, so that the felt-like fiber layer and the porous metal are heated. A clad filter material in which the layers are laminated is obtained.

  In order to maintain the fiber of the felt-like fiber layer, the material constituting the felt-like fiber layer is preferably selected to have a lower melting point than the material constituting the porous metal layer. When using a metal fiber having a melting point higher than that of the porous metal layer as a material for the felt-like fiber layer, prepare a metal nonwoven fabric obtained by pressing the metal fiber and use the manufacturing method shown in the first embodiment. When formed, only the vicinity of the contact surface between the porous metal layer and the felt-like fiber layer is softened and joined, so that the fiber layer can be maintained.

  Hereinafter, the present invention will be specifically described with reference to examples. In addition, this invention is not restrict | limited to a following example.

  Example 1 shows a clad filter material in which a perforated nickel foil is attached as a porous metal layer on both sides of a felt-like fiber layer made of a self-bonding nonwoven fabric.

As the self-bonding non-woven fabric, Kuraray Co., Ltd., Vecles MBBK (trade name) (thickness 116 μm, basis weight 40 g / m ² , density 0.341 g / m ² ) was used. The perforated nickel foil as the porous metal layer has a thickness of 9 μm, has a plurality of circular through holes with a diameter of 95 μm, and is formed so that the distances between the centers of the through holes are equal. What was 24% was used. In addition, the perforated nickel foil is a hole formed by forming a resist mold projecting in a substantially hemispherical shape on a substrate using a simple method of screen printing, and then performing electroplating to remove the resist mold. An open nickel foil was used.

  As shown in FIGS. 1 (1) to (3), a copper foil as a press working auxiliary material and a polyimide film as a release film 6 were placed in this order on a press plate 5 (stainless steel plate). Then, the perforated nickel foil 3 / the self-bonding nonwoven fabric 2 / the perforated nickel foil 3 are laminated on the release film 6 in this order, and the release is again performed on the upper surface of the uppermost perforated nickel foil 3. The film 6 and the press plate 5 were laminated (step A).

The material sandwiched between the press plates 5 was placed on the press 4 while maintaining the laminated state. Based on the result of measuring the softening temperature of the surface of the self-bonding nonwoven fabric by applying a press pressure of 8.5 kg / cm ² , heating was performed for 5 minutes at 250 ° C. higher than the softening temperature of the self-bonding nonwoven fabric. . The press machine used was a temperature program controlled heating / cooling molding machine PY-30EA (manufactured by Kodaira Seisakusyo Co., Ltd.). Then, the clad filter material 1 by which the felt-like fiber layer 2 and the perforated nickel foils 3 and 3 (porous metal layer) were bonded together was obtained by lowering the temperature (Step B).

  The SEM observation image which image | photographed the clad filter material obtained in Example 1 from the perforated nickel foil formation surface side is shown in FIG. From FIG. 3, it can be seen that the liquid crystal polymer nonwoven fabric that maintains the fiber and has voids is exposed from the opening of the perforated nickel foil.

  In order to verify the permeability of the clad filter material of Example 1, an aqueous methanol solution used as the fuel of the direct methanol fuel cell was allowed to permeate the clad filter material of Example 1 and the liquid permeation rate was measured. Specifically, the clad filter material was sandwiched and fixed to a glass-type vacuum filter holder (KG25 manufactured by ADVANTEC) so that the perforated nickel foil (porous metal layer) was on the upper and lower surfaces. Place 20 ml of methanol solution (liquid temperature 25 ° C.) with a concentration of 12.3 mol / L into a funnel with a capacity of 22 ml arranged on the upper surface side of the fixed clad filter material, and pass through without depressurization. The time required for the methanol aqueous solution to decrease from 15 ml to 5 ml, that is, the time required for 10 ml of the methanol aqueous solution to permeate was measured. Moreover, the permeation | transmission rate of methanol aqueous solution was measured separately on the same conditions as the above about the said perforated nickel foil single-piece | unit used as a porous metal layer, and the said self-bonding nonwoven fabric used as a felt-like fiber layer.

  As a result, the clad filter material of Example 1 required 139 seconds for the funnel aqueous methanol solution to decrease from 15 ml to 5 ml. On the other hand, the permeation time of the perforated nickel foil was 25 seconds, and the permeation time of the self-bonding nonwoven fabric was 30 seconds. From this result, the methanol aqueous solution permeation time of the clad filter material of Example 1 is a simple sum of the permeation speeds of the self-bonding nonwoven fabric as the material used for the clad filter material and two perforated nickel foils. It took much longer than 80 seconds.

  Furthermore, the corrosion resistance of the perforated nickel foil was tested. That is, 100 ml of a test solution consisting of 50 vol% methanol, 49 vol% water and 1 vol% formic acid was placed in a 200 ml conical beaker, and a 3.5 cm square perforated nickel foil was placed therein, and the test solution was 1 at 27 ° C. (room temperature). Left for a week. The amount dissolved in the test solution after standing for 1 week was measured by ICP method and quantitatively analyzed. As a result, the dissolution amount of nickel was 230 ppm or less.

  Example 2 shows an example of a clad filter material in which a perforated nickel foil having fewer openings than the perforated nickel foil of Example 1 is attached to both sides of a felt-like fiber layer.

  For the felt-like fiber layer, the same self-bonding nonwoven fabric as in Example 1 was used under the same conditions. The perforated nickel foil as the porous metal layer has a thickness of 9 μm, has a plurality of circular through holes with a diameter of 50 μm, and is formed so that the distances between the centers of the through holes are equal. The one with a rate of 5% was used.

  As the perforated nickel foil, one produced by a photoresist method using a dry film excellent in fine processing and suitable for the production of a fine perforated metal foil was used. That is, a dry film (thickness 25 μm) is pasted on the surface-treated substrate, a photomask corresponding to the surface shape of the perforated metal foil to be prepared is placed on the top surface of the dry film, and then irradiated with ultraviolet rays. The dry film was exposed and developed to partially cure the photoresist, and unnecessary portions were removed to produce a protruding mold, and after electrolytic plating, the mold was removed.

  In the same manner as in Example 1, a copper foil as a press working auxiliary material and a polyimide film as a release film were sequentially placed on a press plate (stainless steel plate). And it laminates in order of perforated nickel foil / self-bonding non-woven fabric / perforated nickel foil on the release film, and on the upper surface of the uppermost perforated nickel foil, again, the release film, copper foil, The press plates were stacked in the order (step A).

The material sandwiched between the press plates was placed on a press while maintaining the laminated state, applied with a press pressure of 8.5 kg / cm ² , and heated at 250 ° C. for 5 minutes. Then, the clad filter material with which the felt-like fiber layer and the perforated nickel foil (porous metal layer) were bonded together was obtained by lowering the temperature (Step B).

  The SEM observation image which image | photographed the clad filter material obtained in Example 2 from the perforated nickel foil formation surface side is shown in FIG. When FIG. 4 is seen, like Example 1, it turns out that the self-bonding nonwoven fabric which maintains a fiber and has a space | gap is exposed from the opening part of perforated nickel foil.

  The clad filter material of Example 2 was permeated with a methanol aqueous solution (liquid temperature 25 ° C.) having a concentration of 12.3 mol / L in the same manner as in Example 1, and the liquid permeation rate was measured. As a result, the clad filter material of Example 2 required 650 seconds for the funnel aqueous methanol solution to decrease from 15 ml to 5 ml. Moreover, when the liquid permeation rate of only the perforated nickel foil was measured as in Example 1, it took 27 seconds. From this result, the permeation time of the aqueous methanol solution of the clad filter material of Example 2 is a simple sum of the permeation speeds of the self-bonding nonwoven fabric as the material used for the clad filter material and two perforated nickel foils. It took much longer than 84 seconds.

  Furthermore, the corrosion resistance of the perforated nickel foil was tested. Under the same conditions as in Example 1, a 3.5 cm square perforated nickel foil was placed in the test solution and allowed to stand at 27 ° C. (room temperature) for 1 week. The amount dissolved in the test solution after standing for 1 week was measured by ICP method and quantitatively analyzed. As a result, the dissolution amount of nickel was 156 ppm.

  Compared with the case of Example 1, the clad filter material of Example 2 was significantly slowed in the liquid permeation rate, and the permeation rate could be prolonged. As a result, it was shown that the permeation speed can be adjusted by adjusting the opening condition of the porous metal layer.

  Example 3 shows a clad filter material in which a perforated copper foil is attached as a porous metal layer on both sides of a felt-like fiber layer made of the same self-adhesive resin as in Example 1.

  First, the perforated copper foil will be described. As the perforated copper foil, one having a plurality of circular holes having an average diameter of 15 μm and an aperture ratio of 1% manufactured by a photoresist method using a dry film was used. First, a method for producing a perforated copper foil will be described.

  A dry film (thickness 15 μm) is pasted on the carrier copper foil (thickness 35 μm), and then a photomask corresponding to the surface shape of the perforated metal foil to be produced is placed on the upper surface of the dry film, and then ultraviolet rays are applied. The dry film was exposed and developed by irradiation to partially cure the photoresist, and unnecessary portions were removed to form a resist mold consisting of cylindrical protrusions having a diameter of 15 μm.

  A release layer was formed on the carrier copper foil on which the resist mold was formed. The release layer is formed between the carrier copper foil and the perforated copper foil so as to be easily peeled when the carrier copper foil is finally removed from the perforated copper foil. The release layer was formed by adjusting 3.5 g / L of carboxybenzotriazole to pH 5.0 using sulfuric acid, setting the bath temperature to 40 ° C., and immersing in this solution for 15 seconds.

  Subsequently, a 10 μm thick copper plating layer was formed on the resist mold by electrolytic copper plating. The bath composition and electrolytic conditions for electrolytic copper plating are shown below.

Bath composition: Copper sulfate pentahydrate 250g / L
Copper sulfate 192g / L
Electrolysis conditions: Liquid temperature 40 ° C
Current density 20A / dm ²
The anode electrode was an insoluble electrode (DSE) and a direct current power source was used.

  Next, the resist mold was peeled and removed using an amine-based resist remover (Melstrip DF3820 manufactured by Meltex). As a result, a plurality of circular holes having a diameter of 15 μm were formed in the copper foil.

  The perforated copper foil after stripping the resist was pickled and then roughened. The roughening treatment was a two-stage roughening treatment comprising a first roughening treatment layer and a second roughening treatment layer. The first roughening treatment layer was overplated. Below, the bath composition and electrolysis conditions of the covering metal plating of a 1st roughening process layer are shown.

Bath composition: Copper 13.7 g / L
Sulfuric acid 150g / L
Electrolysis conditions: Liquid temperature 25 ° C
Current density 30A / dm ²
Static bath, 5 seconds

  After forming the first roughening treatment layer, a second roughening treatment layer was further formed. The bath composition and electrolysis conditions of the second roughening treatment layer are shown below.

Bath composition: Copper 65g / L
Sulfuric acid 90g / L
Electrolysis conditions: Liquid temperature 48 ° C
Current density 20A / dm ²
Air stirring in a square tank, 10 seconds

  The plating treatment of the first roughening treatment layer and the second roughening treatment layer is repeated twice in order, and after the roughening treatment, the surface roughness (Rzjis) on the roughening treatment surface side of the perforated copper foil is 5 .8 μm. The surface roughness (Rzjis) is measured in the TD direction in accordance with JIS B 0601.

  The SEM observation image which image | photographed the roughening surface side of the perforated copper foil after a roughening process is shown in FIG. When FIG. 5 is seen, it is clear that the unevenness | corrugation is formed in the surface of perforated copper foil, and is processed roughly.

  Next, the carrier copper foil was physically peeled from the perforated metal foil at the part of the peeling layer previously formed on the surface of the carrier copper foil.

  Tin-nickel alloy plating treatment was performed on both sides of the perforated copper foil after the carrier copper foil was peeled off, and the tin-nickel alloy plating was coated with a thickness of 2 μm per side. The bath composition and electrolysis conditions for tin-nickel alloy plating are shown below.

Bath composition: Tin chloride 28g / L
Nickel chloride 30g / L
Potassium pyrophosphate 200g / L
Glycine 20g / L
Electrolysis conditions: Liquid temperature 50 ° C
pH 8
Cathode current density 1A / dm ²

  An appropriate amount of aqueous ammonia was added according to the state of internal stress generation. The tin-nickel alloy plating film had an electrodeposition weight ratio of Sn / (Sn + Ni) = 0.73. Moreover, the surface roughness (Rzjis) of both surfaces of the perforated copper foil after tin-nickel alloy plating coating was 7.3 μm.

  Moreover, between each process, it pickled and washed with water suitably, and aimed at the improvement of the fixing property between each formed layer. Specifically, a method of pickling with an acid solution such as dilute sulfuric acid or a mixed solution of dilute sulfuric acid and hydrogen peroxide, followed by washing with water such as pure water or ion-exchanged water and drying was adopted.

  In the same manner as in Example 1, a copper foil as a press working auxiliary material and a polyimide film as a release film were sequentially placed on a press plate (stainless steel plate). And it laminates in order of perforated copper foil / self-bonding nonwoven fabric / perforated copper foil on the release film, and on the upper surface of the uppermost perforated copper foil, again, the release film, copper foil, The press plates were stacked in the order (step A).

The material sandwiched between the press plates was placed on a press while maintaining the laminated state, applied with a press pressure of 8.5 kg / cm ² , and heated at 250 ° C. for 5 minutes. Thereafter, the clad filter material in which the felt-like fiber layer and the perforated copper foil (porous metal layer) were bonded together was obtained by lowering the temperature (step B). At this time, almost no exudation of the resin component of the liquid crystal polymer nonwoven fabric was observed. The SEM observation image which image | photographed the clad filter material obtained in Example 3 from the porous metal layer side is shown in FIG.

  The clad filter material of Example 3 was permeated with a methanol aqueous solution (liquid temperature 25 ° C.) having a concentration of 12.3 mol / L in the same manner as in Example 1, and the liquid permeation rate was measured. As a result, the clad filter material of Example 3 required 2000 seconds for the funnel aqueous methanol solution to decrease from 15 ml to 5 ml. Moreover, when the liquid permeation speed of only the perforated copper foil was measured as in Example 1, it took 35 seconds. From this result, the permeation time of the aqueous methanol solution of the clad filter material of Example 3 is a simple sum of the permeation speeds of the self-bonding nonwoven fabric as the material used for the clad filter material and two perforated copper foils. It took much longer than 105 seconds.

  Moreover, in the clad filter material of Example 3, the perforated copper foil and the self-bonding nonwoven fabric exhibited adhesion without problems in handling.

  Furthermore, the corrosion resistance of the perforated copper foil was tested. Under the same conditions as in Example 1, a 3.5 cm square perforated copper foil was placed in the test solution and left at 27 ° C. (room temperature) for 1 week. The amount dissolved in the test solution after standing for 1 week was measured by ICP method and quantitatively analyzed. As a result, the amount of dissolution was 0.5 ppm or less for both tin and nickel.

  The clad filter material of Example 3 was able to significantly slow the liquid permeation rate as compared with Examples 1 and 2. As a result, it was shown that the permeation speed can be adjusted by adjusting the opening condition of the porous metal layer.

  From the above, it was shown that the cladding filter materials shown in Examples 1 to 3 can suppress the permeation rate of a high concentration aqueous methanol solution. When such a clad filter material is used as a permeable membrane of a direct methanol fuel cell, the material permeation rate can be adjusted to a rate at which methanol crossover can be suppressed. In addition, when the clad filter material supporting the catalyst is disposed in the fuel discharge section in the fuel storage section, the decomposition of methanol can be efficiently promoted and crossover can be suppressed.

  The clad filter material and the method for producing the clad filter material according to the present invention can control the permeation speed, which has been difficult in the prior art, and as a result, can control the residence time of substances (liquid, gas) in the clad filter material. Yes, and downsizing can be realized. Therefore, for example, components of fuel cells using methanol, such as direct methanol fuel cells, current collectors of secondary batteries and capacitors, catalyst carriers that promote chemical reactions, screen devices for fine powder classification, solid-liquid separation Screen equipment for processing, vents of various containers and equipment, dustproof filters, liquid antibacterial filters, liquid reforming filters for imparting metal ions to liquids and reforming liquids such as drinking water, silencers, heat exchangers, It can be used for electromagnetic shielding, magnetic materials, conductive materials, and a wide range of other fields.

It is a schematic diagram which shows the example of a manufacturing process of the clad filter material which concerns on this invention. It is a schematic diagram which shows the example of the opening shape of the perforated metal foil used in the clad filter material which concerns on this invention. It is a SEM observation image which image | photographed the clad filter material of Example 1 from the porous metal layer side. It is a SEM observation image which image | photographed the clad filter material of Example 2 from the porous metal layer side. 4 is an SEM observation image obtained by photographing the state of the roughened surface in the perforated metal foil used for the clad filter material of Example 3. It is a SEM observation image which image | photographed the clad filter material of Example 3 from the porous metal layer side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cladding filter material 2 ... Felt-like fiber layer 3 ... Porous metal layer

Claims (12)

A plate-like filter material capable of transmitting gas or liquid from one side to the other side,
The filter material is a composite multilayer material in which a porous metal layer is bonded to one or both sides of a felt-like fiber layer. The clad filter material according to claim 1, wherein the porous metal layer uses a perforated metal foil. The clad filter material according to claim 1, wherein the porous metal layer is a porous sponge-like metal sheet material. The porous metal layer is made of any material of copper, copper alloy, titanium, titanium alloy, tantalum, tantalum alloy, niobium, niobium alloy, nickel, nickel alloy, vanadium, platinum, palladium, heat-resistant aluminum, and stainless steel. The clad filter material in any one of Claims 1-3. The clad filter material according to claim 1, wherein the porous metal layer has a thickness of 1 μm to 500 μm. The said felt-like fiber layer is a clad filter material in any one of Claims 1-5 which used the metal nonwoven fabric which consists of metal fibers. The clad filter material according to any one of claims 1 to 5, wherein the felt-like fiber layer is a resin nonwoven fabric made of resin fibers. The clad filter material according to claim 7, wherein the resin fiber is a self-bonding nonwoven fabric. The felt-like fiber layer uses a catalyst-supporting fiber supporting any one of a platinum-based catalyst component, a palladium-based catalyst component, a gold-based catalyst component, and an iron-based catalyst component on the fiber surface, and one or more of these are used. The clad filter material according to any one of claims 6 to 8, wherein a catalyst-supporting nonwoven fabric obtained by combining the two is used. The clad filter material according to any one of claims 1 to 5, wherein the felt-like fiber layer is a composite fiber nonwoven fabric in which two or more of the resin fibers, the catalyst-supporting fibers, and the metal fibers are combined. It is a manufacturing method of the clad filter material in any one of Claims 1-10, Comprising: It is set as a clad filter material through the following process A and process B, The manufacturing method of the clad filter material characterized by the above-mentioned.
Step A: A perforated metal foil or a porous sponge-like metal sheet constituting the porous metal layer is brought into contact with one or both sides of the felt-like fiber layer to form a laminated state.
Step B: While maintaining the lamination state, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered to bond the felt-like fiber layer and the porous metal layer. A clad filter material is obtained. It is a manufacturing method of the clad filter material in any one of Claims 1-10, Comprising: It becomes a clad filter material through the following process a-process c, The manufacturing method of the clad filter material characterized by the above-mentioned.
Step a: Using one or more of resin fibers, catalyst-supporting fibers, and metal fibers for constituting the felt-like fiber layer, selection or blending of raw material fibers for constituting the felt-like fiber layer And adjust the raw fiber.
Step b: Raw material constituting the felt-like fiber layer in accordance with the layer structure (porous metal layer / felt-like fiber layer or porous metal layer / felt-like fiber layer / porous metal layer) of the clad filter material to be manufactured The fibers are brought into contact with a perforated metal foil or a sponge-like metal sheet material constituting the porous metal layer to form a laminated state.
Step c: While maintaining the laminated state obtained in the step b, press pressure is applied, heating is performed at a temperature equal to or higher than the softening temperature of the felt-like fiber layer surface, and then the temperature is lowered, so that the felt-like fiber layer and the porous layer are porous. A clad filter material in which a metal layer is bonded is obtained.

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