JPH11217602A - Manufacture of porous copper body and porous copper tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of efficiently manufacturing a porous copper body and a porous copper tube, where mutual copper powder particles are subjected to metallic bond and large surface area and excellent thermal conduction are provided and also the improvement in the heat exchange efficiency of a thermal conductor is made possible by fitting in or on the thermal conductor. SOLUTION: This method of manufacture of the porous copper body has the following stages: (a) a stage where a copper powder is temporarily joined to a synthetic resin sheet with an organic binder to form a pretreated body; (b) a stage where the pretreated body is heated and held under an oxidizing atmosphere to form an oxidation treated body having a structure in which mutual copper powder particles are bridged by means of oxides formed on respective surfaces of the copper powder particles; (c) a stage where the oxidation treated body is heated and held under a reducing atmosphere to form the porous copper body in which mutual copper powder particles are joined to each other by means of metallic bond.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper porous body formed by joining copper powders into various shapes such as a plate, and a copper porous tube formed by joining copper powders into a tubular shape. And a method for producing the same. The copper porous body and the copper porous tube according to the present invention are applicable to heat-related fields such as heat exchanger piping, heat pipes, and hot and cold water supply piping, as well as household appliances and factories utilizing filters and sterilization. It can be used as a material for manufacturing equipment.

[0002]

2. Description of the Related Art Conventionally, as a technique for forming a porous layer made of metal on the surface of a metal material, for example, the following techniques are known. Japanese Patent Application Laid-Open No. 60-103187 discloses a method for manufacturing a heat exchanger tube, which comprises forming a coating of a copper-tin-bismuth alloy on the surface of a steel tube. Japanese Patent Application Laid-Open No. S60-251390 discloses a method in which a low melting point solder (joining powder) of about 500 mesh and a material powder composed of copper pieces of 200 mesh or less are put on the inner surface of a copper tube (envelope). A method for manufacturing a heat pipe is disclosed in which these powders are heated and welded while being rotated in a circumferential direction. Japanese Patent Application Laid-Open No. 60-255983 discloses that a magnetic powder coated with a low melting point metal is sprayed on a surface of a metal heat transfer base by using a magnetic field and heated, so that the magnetic powder is transferred to a heat transfer surface. There is disclosed a method for producing a heat exchanger, which is characterized in that the heat exchanger is closely adhered to a heat exchanger. JP-A-61-168
No. 793 discloses a heat transfer tube in which copper powder is sprayed onto the surface of a metal tube by a plasma spraying method to form fine irregularities on the surface, and a method for manufacturing the same. JP-A-62-2
No. 206382 discloses a heat pipe in which a dendritic or granular porous layer is formed on the inner surface of a metal tube such as a copper tube by electroplating. JP-A-2-12
No. 9488 discloses a superficially porous tube in which a number of fine open surfaces are formed by dezincing the inner and outer surfaces of a copper-zinc alloy tube. JP-A-2-1758
No. 81 discloses that a mixed layer of a low melting point metal powder (Sn powder) and a high melting point metal powder (Cu powder) is formed on the inner surface of a metal tube.
There is disclosed a method of manufacturing an inner porous tube which heats this to form micropores. JP-A-5-214504 discloses a method of manufacturing a heat transfer tube in which a metal wire is wound around a material tube while spraying metal powder on the surface of the material tube to form a porous sprayed layer, and the metal wire is removed after the sprayed layer is formed. A method is disclosed.

[0003]

Among the above-mentioned prior arts, the method of forming a porous layer made of copper on the surface of a substrate such as a copper tube using a low-melting metal such as solder or Sn is disclosed in US Pat. Since the base such as a tube and the porous layer made of copper are joined via a low melting point metal such as solder or Sn,
The heat conduction becomes poor at the low melting point metal, and as a result,
There is a problem that the heat conduction loss between the porous layers increases. Further, when low melting point solder or the like is used, there is a problem that heat resistance and chemical resistance are deteriorated. Further, a method of providing a copper porous layer or fine irregularities on the surface of a substrate such as a copper tube by a spraying method such as plasma spraying, or by electroplating,
There was a problem that it took time to manufacture.

According to the present invention, it is possible to improve the heat exchange efficiency of a heat transfer body by fitting the copper powder to each other, having a large surface area, good heat conduction, and fitting inside or outside the heat transfer body. It is an object of the present invention to provide a possible copper porous body and a method for efficiently producing a copper porous tube. Further, the present invention can be formed into various shapes such as a plate shape, a tubular shape, a container shape, and the like, by bonding copper powders to each other, and has a gas permeability, a liquid permeability, and a bactericidal property,
It is an object of the present invention to provide a method for producing a porous copper body that can be used as a filter, a household tool utilizing antibacterial properties, and a material for manufacturing equipment in a factory.

[0005]

According to the present invention, there is provided a method for producing a porous copper body, comprising the steps of: (a) temporarily preparing copper powder on a synthetic resin sheet with an organic binder to produce a pretreated body;
(B) a step of heating and holding the pre-treated body in an oxidizing atmosphere to form an oxidized body having a structure in which the copper powders are cross-linked by oxides generated on respective surfaces; A step of heating and maintaining the treated body in a reducing atmosphere to form a copper porous body in which the copper powders are joined by metal bonding.

The method for producing a copper porous tube according to the present invention comprises:
(I) Copper powder is temporarily bonded to a synthetic resin sheet with an organic binder, and the copper powder on the synthetic resin sheet is transferred to the surface of a tubular or columnar support made of a material that does not sinter with copper oxide. A process of preparing a pretreatment tube instead;
(Ii) a step of heating and maintaining the pretreatment tube in an oxidizing atmosphere to form an oxidation treatment tube having a structure in which the copper powders are cross-linked by oxides generated on respective surfaces; (iii)
Withdrawing the oxidation treatment tube from the support surface,
(Iv) heating and maintaining the oxidation treatment tube under a reducing atmosphere;
A step of forming a copper porous tube in which the copper powders are joined by metal bonding.
The copper porous tube manufactured by this method is a tube in which copper powder is metal-bonded to each other to form a tubular shape. The surface area of the tube can be increased, and the heat exchange efficiency can be increased.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, copper powder is temporarily joined to a synthetic resin sheet with an organic binder, and the surface of the copper powder is once oxidized. As a result, a structure in which the copper powder is cross-linked (bridged) with the oxide is obtained. Then, by heating this in a reducing atmosphere, the surface of the copper powder is reduced, and at the same time, the oxide bond between the copper powder and the copper powder becomes a metal bond, and the copper powder is tightly bonded to each other by the metal bond. Is produced. This copper porous body can be made into a copper tube with excellent heat exchange efficiency by being inserted or extrapolated into a copper tube and applied to a heat pipe or a pipe for a heat exchanger. In addition, it can be formed into various shapes such as a plate, a tube, and a container, and has air permeability, liquid permeability, and antibacterial property,
It can be used as a filter, a household tool using antibacterial properties, and a material for manufacturing equipment in a factory.

[0008] Coarse copper powder having a particle size of 0.1 mm or more does not easily sinter even when simply heated in an inert atmosphere or a reducing atmosphere. Therefore, in the present invention, after the copper powder is temporarily joined with an organic binder, the copper powder is sintered (sintered) together by two-stage sintering of oxidation and reduction. If all the copper is oxidized in the oxidation step, the strength of the copper powder itself is reduced, so only the surface of the copper powder is oxidized. Further, if the temperature is lowered once in a state of being oxidized at a high temperature, the surface oxide is peeled off from the surface of the copper powder due to the difference in thermal expansion coefficient between Cu and Cu oxide. Therefore, in the present invention, it is desirable that after oxidation, reduction is performed while maintaining the temperature at a high temperature.

In the present invention, the copper powder of the material is pure copper (C
u), Cu-P alloy (phosphor bronze), Cu-Be alloy (beryllium bronze), Cu-Sn alloy (bronze), Cu-Al alloy, Cu-Si alloy, Cu-Ni alloy, or mainly copper Although an alloy to which more than one kind of element is added can be used, it is particularly preferable to use pure copper. In addition, the particle size of the copper powder can achieve the function required for the copper porous body to be produced, that is, an improvement in heat exchange efficiency and an increase in surface area,
Moreover, the copper porous body formed may be appropriately selected so as to have sufficient mechanical strength, and usually has an average particle size of 0.1 to 3 m.
m, preferably about 0.2 to 2 mm.
Further, in order to arrange the copper powder 3 densely, it is desirable to make the particle diameter of the copper powder 3 as uniform as possible.

An example of a method for producing a porous copper body according to the present invention will be described with reference to FIGS. In this method, first,
An organic binder is applied onto the synthetic resin sheet 1, then copper powder 3 is scattered, and the copper powders 3 are temporarily joined with the organic binder 2 to obtain a copper powder sheet 10 having a desired shape such as a flat plate shape or a tubular shape (a). Perform the process. The synthetic resin sheet 1 is made of polyethylene,
Various materials such as polypropylene, EVA resin, vinyl chloride resin, vinylidene chloride resin, and fluororesin can be used. Further, as the organic binder 2, a material which is easily lost in the subsequent step of heating and holding the copper powder in an oxidizing atmosphere and does not leave extra ash or carbon in its traces is preferable. For example, glycerin, oil (mineral Oils, animal and vegetable fats and oils), and organic adhesives such as acrylic resin-based and cellulose resin-based adhesives. For convenience, a commercially available spray-type acrylic resin adhesive may be used to spray-coat the copper powder 3 spread on the synthetic resin sheet 1.

In the oxidation treatment step of the copper powder sheet 10, it is desirable to perform the oxidation treatment step after transferring to the surface of the support 5 made of a material that does not sinter with the copper oxide. The material of the support 5 is stainless steel, Ni-based alloy, Co
Base alloy, glass, carbon, BN (boron nitride) and the like are used. When the copper powder sheet 10 is transferred to the support 5, it is desirable to apply a silicone-based or fluororesin-based release material to the surface of the synthetic resin sheet 1.

Next, the support 5 on which the copper powder sheet 10 is placed is placed in an atmosphere heating furnace or the like, and is heated and maintained at 400 to 700 ° C. in an oxidizing atmosphere, preferably in air. The step (b) of forming an oxidized body 11 having a structure in which the powders 3 are crosslinked by the oxides 4 generated on the respective surfaces is performed. When the heating temperature in this oxidizing atmosphere is lower than 400 ° C., the amount of oxides generated on the surface of the copper powder 3 is reduced, the bonding strength between the copper powders 3 is reduced, and the copper powders 3 are easily broken. On the other hand, when the heating temperature exceeds 700 ° C., the copper powder 3 is softened and may be deformed or have reduced strength.
The time for heating and holding the copper powder sheet 10 under an oxidizing atmosphere is not particularly limited as long as a structure in which the copper powders 3 are sufficiently bonded to each other by the cross-linking structure of the oxide is obtained as described above. About 3 hours, preferably 15 minutes to 1
About an hour. As the oxidizing gas used in the step (b), pure oxygen gas, oxygen gas diluted with nitrogen gas or carbon dioxide gas, nitrous oxide gas, and the like can be used in addition to the above air.

Next, the surroundings of the oxidized body 11 are heated and held in a reducing atmosphere, and as shown in FIG. 3, the copper powder 3 is bonded to other copper powder 3 by metal bonding to form a copper porous material having a mesh structure. Step (c) for forming the body 12 is performed. here,
After a heating step in an oxidizing atmosphere, if a reducing gas such as hydrogen gas is immediately introduced into an atmosphere heating furnace in which the oxidized body 11 is placed, combustion may occur. In order to prevent this, after the step (b), the surroundings of the oxidized body 11 are replaced with an inert gas atmosphere while maintaining the temperature of the oxidized body 11 or while shifting to the processing temperature of the step (c). After that, it is desirable to carry out the step (c) by replacing the atmosphere with a reducing atmosphere. By changing the oxidizing atmosphere to the reducing atmosphere without changing the temperature of the copper powder 3, it is possible to prevent the inconvenience that the copper oxide is separated due to the difference in the thermal expansion coefficient between the copper and the copper oxide. it can. As the inert gas used here, nitrogen gas, argon gas, helium gas or the like is used, and preferably, nitrogen gas is used. In addition, as a reducing gas for forming a reducing atmosphere, a carbon monoxide-containing gas such as hydrogen gas, hydrogen gas diluted with nitrogen gas, butane decomposition gas, carbon monoxide gas, water gas, and generator gas is used. Hydrogen gas and hydrogen gas diluted with nitrogen gas are particularly suitable.

The heating temperature when heating the oxidized body 11 in a reducing atmosphere is 300 to 700 ° C., preferably 40 to 700 ° C.
The temperature is set to about 0 to 600 ° C. When the heating temperature is lower than 300 ° C., the reduction is not sufficient, and the copper oxide remains,
(B) The temperature difference from the step is increased, and the oxide is easily peeled. When the heating temperature exceeds 700 ° C., the copper powder is softened and may be deformed or its strength may be reduced. The time during which the oxidized body 11 is heated and held under a reducing atmosphere is not particularly limited as long as a structure in which the copper powders 3 are firmly joined to each other by metal bonding is obtained as described above, but is usually about 10 minutes to 3 hours. Preferably, it is about 15 minutes to 1 hour.

The above steps (a) to (c) are sequentially performed,
By leaving it to cool in a reducing atmosphere and taking it out of the furnace, a copper porous body 12 in which copper powders 3 are joined vertically and horizontally by strong metal bonding as shown in FIG. 3 is obtained. This copper porous body 12 has an opening between the joined copper powders,
The openings have air permeability and liquid permeability. Moreover, since it consists of copper or a copper alloy, and each copper powder is joined by metal bonding, it is excellent in heat conduction and has a large surface area. In addition, the use of copper has antibacterial properties for preventing the growth of microorganisms such as bacteria. From these characteristics, this copper porous body 12 can be inserted or extrapolated into a copper pipe and applied to a heat pipe or a pipe for a heat exchanger,
A copper tube having excellent heat exchange efficiency can be obtained. In addition, it can be formed into various shapes such as a plate, a tube, and a container,
It has air permeability, liquid permeability, and antibacterial properties, and can be used as a filter, a household tool using antibacterial properties, a material for manufacturing equipment in a factory, and the like.

The copper porous body 12 can be subjected to an appropriate forming process such as rounding, punching, shallow drawing, welding, etc., depending on the intended use. FIG. 4 shows, as an example, the copper porous body 12 formed by punching out a base material of the copper porous body 12 formed in a plate shape into a circle and forming a suitable shape as a filter. In addition, a cylindrical body produced by rounding and a disk body can be welded or brazed to form a liquid-permeable container body (bottomed cylindrical body). This container body can be used as a drain filter at home and a trash can for a sink, utilizing its liquid permeability and antibacterial properties.

Next, an example of a method for manufacturing a porous copper tube according to the present invention will be described with reference to FIGS. in this way,
The same copper powder 3, synthetic resin sheet 1, and organic binder 2 as in the example of the method for producing a porous copper material described above can be used. In this method, first, an organic binder is applied onto the synthetic resin sheet 1 and copper powder is temporarily joined to form a flat copper powder sheet 10 shown in FIG. 1, and then the synthetic resin sheet 1 is supported in a cylindrical or columnar shape. The copper powder sheet 10 was wound around the outer peripheral surface of the body 6 and transferred to the outer peripheral surface of the support 6, and the copper powder 3 was temporarily joined to the outer periphery of the support 6 to form a cylindrical shape as shown in FIG. 5. Step (i) of preparing the pretreatment tube 13 is performed. It is desirable to apply a release material on the synthetic resin sheet 1 in order to facilitate the peeling of the copper powder sheet 10. When transferring the copper powder sheet 10, it is desirable to apply an organic binder on the copper powder sheet 10 or on the outer peripheral surface of the support 6. As the support 6, a cylinder or a column made of the same material as the support 5 used in the above-described example of the method for producing a porous copper material, particularly preferably stainless steel, is used.

Next, the support 6 around which the pretreatment tube 13 is wound is placed in an atmosphere heating furnace or the like, and heated and maintained at 400 to 700 ° C. in an oxidizing atmosphere, preferably in air, so that the copper powders 3 (Ii) step of forming an oxidation treatment tube 14 having a structure cross-linked by the oxide 4 generated on the surface of the substrate. The time required for this step is not particularly limited, but is usually about 10 minutes to 3 hours, preferably about 15 minutes to 1 hour. As the gas to be used, besides air, pure oxygen gas, oxygen gas diluted with nitrogen gas or carbon dioxide gas, nitrous oxide gas, or the like can be used.

Next, as shown in FIG. 6, a step (iii) of extracting the oxidation treatment tube 14 from the support 6 is performed. When the oxidation treatment is performed, a bridge structure is formed between the copper powders 3 due to the formation of the oxide 4 on the surface of the copper powders 3 and the copper powders 3 are formed.
Slightly expands. As a result, the oxidation treatment tube 14 is easily separated from the outer peripheral surface of the support 6 and is easily extracted. When the next reduction treatment is performed with the oxidation treatment tube 14 attached to the support 6, the oxide between the copper powders 3 is reduced to form a metal bond between the copper powders 3 and the copper powders 3 shrink. As a result, the copper porous tube may not come off from the support 6. (Ii)
After the completion of the process, the oxidation treatment tube 14 is removed from the support 6.
Can be easily extracted. At this time, the oxidation treatment tube 1
4 so that the temperature of the oxidation treatment tube 14 is not suddenly lowered.
Is desirably left in the furnace, and the support 6 is pulled out of the furnace.

Next, the surroundings of the oxidation treatment tube 14 are heated and held in a reducing atmosphere, and the copper powders 3 are joined together by strong metal bonding to form a circular copper tubular tube 15 (iv). Is carried out. When replacing the furnace in an oxidizing atmosphere with a reducing atmosphere, while maintaining the furnace temperature,
It is desirable that the inside of the furnace is once set to an inert gas atmosphere such as a nitrogen gas or an argon gas, and then a reducing gas is introduced.
As the reducing gas, a hydrogen gas, a hydrogen gas diluted with a nitrogen gas, a carbon monoxide gas, a water gas, a butane decomposition gas, a carbon monoxide-containing gas such as a generating furnace gas can be used,
Particularly, hydrogen gas diluted with hydrogen gas or nitrogen gas is preferable. Further, the heating temperature of this reduction treatment is 300 to 70
0 ° C., preferably about 400 to 600 ° C. The processing time is not particularly limited, but is usually about 10 minutes to 3 hours,
Preferably, it is about 15 minutes to 1 hour.

By sequentially performing the above steps (i) to (iv), a copper porous tube 15 having a circular tubular shape obtained by joining the copper powders 3 with each other by strong metal bonding is obtained. The copper porous tube 15 has openings between the joined copper powders, and has air permeability and liquid permeability due to the openings. In addition, since the copper powders are joined by metal bonding, they have excellent heat conduction and a large surface area. In addition, the use of copper has antibacterial properties for preventing the growth of microorganisms such as bacteria. Due to these features, the copper porous tube 15 can be made into a copper tube having excellent heat exchange efficiency by being inserted or extrapolated into the copper tube and applied to a heat pipe or a pipe for a heat exchanger. In addition, since it has air permeability, liquid permeability, and antibacterial properties, it can be used as a filter, a household tool using antibacterial properties, a material for manufacturing equipment in a factory, and the like.

FIG. 7 exemplifies a copper tube 16 having a copper porous tube 15 and having a copper porous layer with improved heat exchange efficiency. The copper tube 16 has a copper tube 7 having an outer diameter equal to or slightly smaller than the inner diameter of the copper tube 7 inserted into the copper tube 7 having a smooth inner and outer surface. Tube 7
Copper porous tube 15 having an inner diameter equal to or slightly larger than the outer diameter of
Has been fitted. Copper tube 7 and inner and outer copper porous tubes 15,1
5 is desirably fixed by a slight rolling process or joining means such as spot welding. By forming the copper porous layer by interpolating and extrapolating the copper porous tubes 15, 15, the copper tube 16 has an improved surface area and an improved heat exchange efficiency. In addition, the copper tube 7 is connected to the copper porous tube 15,1.
When joining 5, the copper porous tube 15 is not limited to a single layer, and may be joined and integrated by stacking two or more layers.

[0023]

EXAMPLES Examples according to the present invention will be described below, but the present invention is not limited to these examples. (Example 1: Production of a plate-shaped copper porous body) Thickness 0.18 mm
Spray-coated silicone-based mold release material, spray-coated acrylic pressure-sensitive adhesive, spread copper powder made of pure copper with an average particle size of 0.8 mm on it,
A thin copper powder sheet was prepared by temporarily bonding one to three layers of copper powder. After the adhesive was cured, the copper powder sheet was transferred onto a 200 mm × 300 mm stainless steel plate. A stainless steel sheet on which a copper powder sheet is placed is placed in an electric furnace, and the
After heating and holding at 00 ° C. for 1 hour, and then keeping the temperature as it is, the inside of the furnace tube was once replaced with an inert gas (N ₂ ), and then replaced with a reducing gas (H ₂ ).
For 0.5 hours. While the furnace was kept in a reducing atmosphere, the furnace was gradually cooled to obtain a mesh plate-shaped copper porous body in which copper powders were strongly bonded by metal bonding. This plate-like porous body had air permeability and liquid permeability, and was sufficiently usable as a filter or the like. Also, this plate-shaped porous body is
Rounding and bending were possible.

(Example 2: Production of a porous copper tube)
Spray silicone release agent on 18mm polyethylene sheet, spray acrylic adhesive, spray copper powder made of pure copper with average particle size 0.5mm, spray acrylic adhesive A thin copper powder sheet was prepared by applying and temporarily bonding 1 to 3 layers of copper powder. After the adhesive was cured, the copper powder sheet was transferred onto the outer peripheral surface of a stainless steel tube having an outer diameter of 11 mm and a length of 1 m. A stainless steel pipe having a copper powder sheet temporarily bonded to the outer peripheral surface was placed in a tubular electric furnace, and heated and maintained at 550 ° C. for 1 hour in air. After heating and holding, so as to leave the oxidized copper tube in the furnace,
The stainless steel tube was pulled out. Next, while maintaining the temperature as it is, the inside of the furnace tube was temporarily replaced with an inert gas (N ₂ ), and then replaced with a reducing gas (H ₂ ).
C. for 0.5 hour. While the furnace was kept in a reducing atmosphere, the furnace was gradually cooled to obtain a mesh-shaped porous copper tube in which copper powders were strongly bonded by metal bonding. This copper porous tube was externally fitted to a copper tube having an outer diameter of 16 mmφ, rolled, and the copper tube and the copper porous tube were pressed. As a result, a copper tube having a copper porous layer having a large surface area was obtained.

[0025]

According to the present invention, copper powder is metal-bonded to each other,
Efficiently manufacture a copper porous body and a copper porous tube having a large surface area, good heat conduction, and capable of improving the heat exchange efficiency of the heat transfer body by being fitted inside or outside the heat transfer body. A possible method can be provided. Further, according to the present invention, copper powders are metal-bonded to each other to produce copper porous bodies and copper pipes of various shapes such as plate-like, tubular, and container-like shapes. It is possible to easily produce a porous copper body and a porous copper tube having properties and antibacterial properties, and which can be used as a material for a filter, a household tool, a manufacturing facility of a factory, and the like.

[Brief description of the drawings]

FIG. 1 is an enlarged cross-sectional view showing one example of a method for producing a porous copper body according to the present invention and showing a step (a) of producing a copper powder sheet.

FIG. 2 is an enlarged sectional view showing a step (b) of forming an oxidized sheet.

FIG. 3 is an enlarged sectional view showing a step (c) of forming a copper porous body.

FIG. 4 is a perspective view showing a filter which is an example of a porous copper body.

FIG. 5 is a front view showing one example of a method for producing a copper porous tube according to the present invention, and showing a step (i) of producing a pretreatment tube in which a copper powder sheet is transferred to a support.

FIG. 6 is a front view showing the step (iii) of extracting the oxidation treatment tube from the surface of the support.

FIG. 7 is a perspective view showing a state in which a copper porous tube is attached to the copper tube.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 resin sheet 2 organic binder 3 copper powder 4 oxide 5 support 6 support 10 copper powder sheet 11 oxidized body 12 copper porous body 13 pretreatment tube 14 oxidation treatment tube 15 copper porous tube 16 copper porous layer Copper tube

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B21D 53/06 B21D 53/06 Z

Claims (6)

[Claims] (A) a step of temporarily bonding copper powder on a synthetic resin sheet with an organic binder to produce a pretreatment body; and (b) heating and holding the pretreatment body under an oxidizing atmosphere, A step of forming an oxidized body having a structure in which the powders are cross-linked by oxides generated on respective surfaces; (c) heating the oxidized body under a reducing atmosphere;
A step of forming a copper porous body in which the copper powders are joined together by metal bonding. 2. The method for producing a porous copper body according to claim 1, wherein the copper powder on the synthetic resin sheet is used in the step (a).
The pretreated body is formed by transferring to a surface of a support made of a material that does not sinter with copper oxide, the step (b) is performed, and then the oxidized body is removed from the support to remove the (c) A) producing a porous copper body, which comprises carrying out a step. 3. The method for producing a porous copper body according to claim 2, wherein a copper powder is temporarily bonded after applying a release material on the synthetic resin sheet in the step (a). How to make the body. 4. The method for producing a porous copper body according to claim 1, further comprising, after the step (c), a step of rounding the obtained porous copper body. Production method of the body. 5. (i) Temporarily bonding copper powder on a synthetic resin sheet with an organic binder, and transferring the copper powder on the synthetic resin sheet to the surface of a support made of a material that does not sinter with copper oxide. A step of preparing a pretreatment tube instead; (ii) an oxidation treatment tube having a structure in which the pretreatment tube is heated and held in an oxidizing atmosphere, and the copper powders are crosslinked by oxides generated on respective surfaces. (Iii) extracting the oxidized tube from the surface of the support; (iv) heating the oxidized tube under a reducing atmosphere;
Forming a copper porous tube in which the copper powders are joined together by metal bonding. 6. The method for producing a copper porous tube according to claim 5, wherein the copper porous tube obtained in the step (iv) is attached to the copper tube, and the copper tube and the copper porous tube are joined. A method for producing a porous copper tube.