JP3344175B2 - Method for producing porous aluminum body - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an aluminum porous body in which the surface of a three-dimensional net-like plastic substrate having an internal communication space is made of metallic aluminum at a high speed.

[0002]

2. Description of the Related Art Conventionally, as a method for producing a porous aluminum body having a three-dimensional network structure having an internal communication space, a vapor-phase plating method, particularly an arc-type ion plating method, has been applied to a three-dimensional network plastic substrate having an internal communication space. A method is known in which a metal aluminum layer is formed to cover the entire surface of the three-dimensional net-like lattice from the surface portion of the substrate to the innermost portion by vapor deposition of aluminum by a method, and, if necessary, to remove the substrate. (JP-A-6-10077).

[0003]

In the above-described method for producing a porous aluminum body by using the arc ion plating method, the film formation rate is low and there is a problem in productivity.
The equipment cost of the arc type ion plating apparatus is also expensive.

However, using a vacuum deposition method instead of the arc type ion plating method to increase the film forming speed and reduce the equipment cost remains a problem in the adhesion between the plastic substrate and the metal aluminum layer. .

[0005] The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a method for producing a porous aluminum body at low cost, with good adhesion, and at high speed on a plastic substrate having a three-dimensional network structure having an internal communication space.

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that, in a method of manufacturing a porous aluminum body by a vapor phase plating method, a multilayer plating by a combination of different vapor phase plating methods. I focused on the law. Here, the present inventor has found that the adhesion in the vapor phase plating method is determined by the film initially formed on the substrate, particularly the initial film characteristics of several hundred angstroms. By selecting a vapor phase plating method that emphasizes adhesion for the film, and selecting a vapor phase plating method that emphasizes the deposition rate for the second layer film, it is possible to obtain a metal aluminum layer with high adhesion at high speed. Successful.

That is, the present invention provides a method of forming a metal aluminum layer on a three-dimensional net-like plastic substrate having an internal communication space, wherein the first layer on the plastic substrate is formed by an arc ion plating method or a sputtering method. After forming a metal aluminum layer of Å to 1 μm, a metal aluminum layer is formed on the second layer by a vacuum deposition method.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail.

The plastic substrate used in the production of the porous aluminum body in the present invention has a three-dimensional network structure having an internal communication space, and examples thereof include foamed plastic and plastic fiber non-woven fabric. However, of course, the present invention is not limited to these. Any foamed plastic may be used as long as it has an open cell structure. However, it is preferable that the foamed plastic has no cell membrane and is substantially composed of only a skeletal lattice. For example, polyurethane foam from which the cell membrane has been removed is preferably used, but open-cell foams such as polystyrene, polyvinyl chloride, polyethylene, polyisocyanurate, polyphenol, and polypropylene are also preferably used. As the nonwoven fabric of plastic fibers, nonwoven fabrics of various plastic fibers such as polypropylene and polyester can be used.

In this case, the properties of the reticulated plastic substrate are variously selected according to the use of the porous aluminum body, etc.
Generally, the average pore size is preferably several tens of microns or more. Further, although there is no limitation on the shape of the substrate, the thickness is usually 0.05 to 10 mm, and according to the arc-type ion plating method, the average pore diameter, the porosity is small, and the thickness is relatively large. Even when a substrate is used, an aluminum layer can be favorably formed on the innermost lattice surface.

According to the present invention, a metal aluminum layer having a thickness of 200 Å to 1 μm is formed as the first layer on the above-mentioned reticulated plastic substrate by an arc ion plating method or a sputtering method. Here, compared to the vacuum evaporation method of forming a thin film at a heat speed, since the metal aluminum layer is formed by an arc ion plating method or a sputtering method of forming a thin film with ions having kinetic energy greater than the heat speed, The adhesion between the plastic substrate and the metal aluminum layer is improved.

The arc type ion plating method is a method in which a metal target (cathode) is evaporated by arc discharge in a vacuum to coat a metal film on the surface of an object to be processed, and an uneven film is formed. The conditions of the arc-type ion plating method can be appropriately selected, but it is preferable that the degree of vacuum is 1 × 10 ⁻³ to 1 × 10 ⁻⁴ Torr, the arc current is about 100 AH, and the bias voltage is about 30 V. As a result, it is possible to form a metal aluminum layer having a roughness of 200 Å to 1 μm. In addition, since a metal aluminum layer having an uneven shape is formed on the first layer by using an arc-type ion plating method, a metal aluminum layer having an uneven surface is also formed on the second layer.

On the other hand, the sputtering method is a method in which a high voltage is applied to both electrodes in a closed vessel containing a working gas to cause glow discharge, and a plating film is formed by a sputtering phenomenon accompanying the discharge. The sputtering method used here is a direct current bipolar sputtering method, a high frequency sputtering method, a magnetron sputtering method, or the like, but is not limited to these. In this sputtering method, the conditions can be appropriately selected, but the degree of vacuum is 1 × 10 ⁻³ to 1 × 1.
By performing sputtering at 0 ^-1 Torr, a smooth metal aluminum layer having a thickness of 200 Å to 2000 Å can be formed. Note that a smooth metal aluminum layer is formed on the first layer by a sputtering method, so that the surface state of the second layer is also a smooth metal aluminum layer.

In this case, the first metal aluminum layer is formed as extremely thin as 200 Å to 1 μm on the plastic substrate. This is a film thickness for improving the adhesion between the plastic substrate and the metal aluminum layer. When the thickness is smaller than 200 angstroms, the adhesion decreases, and when the metal aluminum layer is formed thicker than 1 micron, high-speed manufacturing is required. The problem remains.

According to the present invention, as described above, after forming a metal aluminum layer of 200 Å to 1 μm on the first layer on the plastic substrate using the arc type ion plating method or the sputtering method, the second layer is formed.
As the layer, a metal aluminum layer is formed using a vacuum deposition method.

Here, the vacuum deposition method is a method in which a metal to be deposited is heated in a vacuum-tight closed vessel to deposit the metal on a substrate, and to perform plating. The conditions of the vacuum deposition can be appropriately selected, but it is preferable to perform the vacuum deposition at 5 × 10 ^{−6 to} 5 × 10 ⁻⁴ Torr. The thickness of the second metal aluminum layer formed by the vacuum deposition is not particularly limited.

In the present invention, the formation of the first metal aluminum layer and the second metal aluminum layer may be performed by separate apparatuses, respectively. It is recommended that the formation be performed sequentially in the same apparatus. That is, the first layer and the second layer of the metal aluminum layer have good adhesion between aluminum and besides the arc type ion plating method or the sputtering method and the vacuum evaporation method are continuously performed in the same apparatus. Since the impurities such as the oxide film do not adhere to the first layer and the second layer without being exposed to the air, the adhesion is further improved.

Here, the outline of this continuous apparatus will be described.
FIGS. 1 and 2 show an example of an apparatus for depositing a metal aluminum layer on a plastic substrate by an arc ion plating method, a vacuum evaporation method, and a sputtering method and a vacuum evaporation method, respectively. (Vacuum chamber), 2 is an aluminum target, 3 is a vacuum pump, 4 is a feed roller for continuously feeding a plastic substrate, 5 is a roller for holding the plastic substrate, 6 is an aluminum evaporation source, and 7 changes the degree of vacuum. 8 is a roller for continuously winding the plastic substrate.

In the apparatus shown in FIG. 1, the front and back surfaces of the three-dimensional net-like plastic sheet (substrate) S fed from the feed roller 4 are made of metal aluminum from an aluminum target by an arc-type ion plating method. After the aluminum layer is formed, first, one side of the sheet S is vacuum-deposited with metal aluminum from the aluminum evaporation source 6, and then the sheet S is inverted and aluminum is vacuum-deposited on the other side of the sheet S. It is to let. In the apparatus shown in FIG. 2, a first aluminum layer is formed on one surface of a three-dimensional net-like plastic sheet (substrate) S fed from the feed roller 4 by a sputtering method. Is vacuum-deposited, the sheet S is inverted, a first aluminum layer is formed on the other surface of the sheet S by a sputtering method, and then aluminum is vacuum-deposited on the other surface.

The thus obtained porous aluminum body of the present invention can be used as it is, that is, with the aluminum layer formed on the grid surface of the reticulated plastic substrate, but the reticulated plastic substrate is removed if necessary. It can be used as a porous aluminum body whose lattice is made of only aluminum, that is, a porous aluminum body composed of only aluminum having the same lattice form as the reticulated plastic substrate.

In this case, the method of removing the reticulated plastic substrate can be appropriately selected according to the type of plastic (melting temperature or thermal decomposition temperature, chemical solubility, etc.).
For example, a method of removing a plastic substrate by melting or thermal decomposition, a method of dissolving plastic with an appropriate organic solvent, and the like are employed.

The aluminum porous body obtained according to the present invention is lightweight, has high corrosion resistance and is inexpensive, and thus is used for various purposes. As a typical example, it is used as a positive electrode support for a lithium ion secondary battery. Used.

[0023]

EXAMPLES The present invention will be described below in detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples and Comparative Example I] Relationship between vapor phase plating method and film forming time Polyester nonwoven fabric (fiber diameter: about 12 microns, thickness: 0.1 mm).
A 5 μm metal aluminum layer was formed under the following film forming conditions at 1 mm and weight 36 g / m ² ), and the film forming times were compared. Table 1 shows the results. Film forming conditions Arc ion plating method Vacuum degree 1 × 10 ⁻⁴ Torr Arc current 100 AH Film forming time 0.6 minutes Vacuum evaporation method Vacuum degree 8 × 10 ⁻⁵ Torr Film forming time 3.7 minutes Sputtering method Vacuum degree 3 × 10 ⁻² Torr Discharge power 600 W Film formation time 1.0 minute Vacuum evaporation method Vacuum degree 8 × 10 ⁻⁵ Torr Film formation time 4.0 minutes Arc ion plating method Vacuum degree 1 × 10 ⁻⁴ Torr Discharge current 100 AH Film formation time 10.0 minutes

[0025]

[Table 1] From the results in Table 1 above, it can be seen that the film forming time of the metal aluminum layer is shorter in the example of the present invention than in the conventional arc ion plating method (single layer).

Example, Comparative Example II A test piece in which a metal aluminum layer was formed and coated on a bent polyester nonwoven fabric under the following film forming conditions was applied to a test piece.
Bending test is repeated 10 times on both sides (20 times in total)
The degree of adhesion between the metal aluminum layer at the bent portion and the polyester nonwoven fabric was compared. Table 2 shows the results. Film forming conditions Arc ion plating method Vacuum degree 1 × 10 ⁻⁴ Torr Arc current 100 AH Film forming time 0.6 minutes Vacuum evaporation method Vacuum degree 8 × 10 ⁻⁵ Torr Film forming time 3.7 minutes Sputtering method Vacuum degree 3 × 10 ⁻² Torr Discharge power 600 W Film formation time 1.0 minute Vacuum evaporation method Vacuum degree 8 × 10 ⁻⁵ Torr Film formation time 4.0 minutes Vacuum evaporation method (single layer) Vacuum degree 8 × 10 ⁻⁵ Torr Film formation Time 4.0 minutes Arc ion plating method Vacuum degree 1 × 10 ^-4 Torr Discharge current 100 AH Film formation time 10.0 minutes

[0027]

[Table 2] [Example, Comparative Example III] Tape test A 90-degree tape test was performed on a test piece obtained by forming a metal aluminum layer on a polyester nonwoven fabric under the following film-forming conditions and coating with a commercially available cellophane tape, and adhered to the tape. The amount of fibrous deposits and the amount of powder deposits were compared (× 40 magnifying glass). Table 3 shows the results. Film forming conditions Arc ion plating method Vacuum degree 1 × 10 ⁻⁴ Torr Arc current 100 AH Film forming time 0.6 minutes Vacuum evaporation method Vacuum degree 8 × 10 ⁻⁵ Torr Film forming time 3.7 minutes Sputtering method Vacuum degree 3 × 10 ^-2 Torr Discharge power 600W Film formation time 1.0 minute Vacuum evaporation method Vacuum degree 8 × 10 ^-5 Torr Film formation time 4.0 minutes Vacuum evaporation method (single layer) Vacuum degree 8 × 10 ^-6 Torr Film formation Time 4.0 minutes Arc ion plating method Vacuum degree 1 × 10 ^-4 Torr Discharge current 100 AH Film formation time 10.0 minutes

[0028]

[Table 3] From the results in Tables 2 and 3, it is recognized that the Example of the present invention has better adhesion of the metal aluminum layer than the vacuum evaporation method (single layer).

[Application Examples] Application Examples as Electrode Materials for Lithium Ion Secondary Batteries A positive electrode active material (manganese dioxide, cobalt oxide, titanium sulfide, etc.) is applied to an electrode support composed of three kinds of aluminum porous bodies of the embodiment. A battery comprising a non-aqueous electrolyte using a filled positive electrode and a lithium-based electrode as a negative electrode, and a positive electrode active material and a conductor (graphite, Characteristics of a battery made of the same non-aqueous electrolyte as above using a positive electrode coated with a mixture obtained by kneading a mixture of carbon and the like and a binder for binding the same and using the same lithium electrode as the negative electrode (Discharge electric capacity and electric output) were compared. Table 4 shows the results.

[0030]

[Table 4] As can be seen from the results in Table 4, those using the aluminum porous body for the electrode support of the positive electrode were all excellent. Further, the alloy according to the present invention exhibited almost the same characteristics as a porous aluminum body manufactured by a single layer using only the arc ion plating method.

FIGS. 3 to 6 show micrographs of the metal aluminum layer. FIG. 3 is a photomicrograph of a film having a thickness of 5 μm formed by an arc ion plating method (single layer), FIG. 4 is a photomicrograph of a film having a thickness of 2000 Å formed by a sputtering method, and FIG. FIG. 6 shows a micrograph formed by a 3 μm film formation + a vacuum evaporation method (a 4.7 μm film formation), and FIG. 6 shows a sputtering method (a 0.06 μm film formation) + a vacuum evaporation method (4.
It is a micrograph formed by (94 micron film formation). As can be seen from FIGS. 3 and 4, a metal aluminum layer having an uneven shape is formed by the arc ion plating method.
It can be seen that a smooth metal aluminum layer is formed by the sputtering method. As can be seen from FIGS. 5 and 6, the first layer on the plastic substrate is formed by an arc-type ion plating method or a sputtering method so that the deposition state of the second layer becomes uneven, It can be seen that a layer is formed. The magnification of each of these micrographs is 750 times.

[0032]

According to the present invention, an aluminum porous body can be manufactured at low cost, with good adhesion, and at high speed on a three-dimensional net-like plastic substrate having an internal communication space.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a continuous processing apparatus of an arc ion plating method and a vacuum deposition method used for carrying out the present invention.

FIG. 2 is a schematic cross-sectional view showing an example of a continuous processing apparatus of a sputtering method and a vacuum evaporation method used for carrying out the present invention.

FIG. 3 is a micrograph showing a 5 μm film formed by an arc ion plating method (single layer).

FIG. 4 is a photomicrograph of a 2000 Å film formed by a sputtering method.

FIG. 5 is a micrograph of a film formed by an arc ion plating method (film formation of 0.3 micron) and a vacuum evaporation method (film formation of 4.7 micron).

FIG. 6 is micrographs formed by a sputtering method (0.06 micron film formation) and a vacuum evaporation method (4.94 micron film formation).

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Reaction apparatus (vacuum chamber) 2 Aluminum target 3 Vacuum pump 4 Delivery roller 5 Roller 6 Aluminum evaporation source 7 Partition plate 8 Winding roller S Plastic sheet (substrate)

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI C23C 14/58 C23C 14/58 Z (72) Inventor Toshinori Murao 1-5-1, Hirakata-shi, Osaka Uemura Industry Co., Ltd. (56) References JP-A-61-76686 (JP, A) JP-A-56-69334 (JP, A) JP-A-5-287520 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58

Claims (4)

(57) [Claims] 1. A method for forming a metal aluminum layer on a three-dimensional net-like plastic substrate having an internal communication space, wherein a first layer on the plastic substrate is formed by an arc ion plating method or a sputtering method.
A method for producing a porous aluminum body, comprising: forming a metal aluminum layer having a thickness of Å to 1 μm, and then forming a metal aluminum layer on the second layer by a vacuum evaporation method. 2. A three-dimensional mesh-like plastic substrate having an internal communication space, after forming a first layer and a second layer of a metal aluminum layer on the three-dimensional mesh-like plastic substrate, removing the substrate, and forming an aluminum comprising a three-dimensional mesh lattice of metallic aluminum. The method for producing a porous aluminum body according to claim 1, wherein a porous body is obtained. 3. The method according to claim 1, wherein the arc-type ion plating or sputtering and the vacuum deposition are performed in the same vacuum chamber. 4. The method according to claim 1, wherein the porous aluminum body is lithium ion 2
4. The method according to claim 1, which is a positive electrode support for a secondary battery.