JPH0931629A - Production of aluminum porous body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce an aluminum porous body inexpensively, with good adhesion and with high speed by forming a metal aluminum layer by a vacuum deposition method after forming a thin film of the metal aluminum on a three- dimentional meshlike plastic substrate by an arc system ion plating method. SOLUTION: In a reactor 1, the three-dimentional meshlike plastic substrate S having an internal communicating space (such as polyurethane foam in which a cell film is removed, and having an average pore size less than several 10μm and a thickness of order of 0.05-10mm) is transmitted from a transmitting roller 4, and the metal aluminum layer having 200Å-1μm thickness is formed as the first layer on both surfaces of the substrate S by the arc system ion plating method. Subsequently metal aluminum is subjected to the vacuum deposition on either surface of the substrate 6 from an aluminum vapor deposition source 6 then, to the vacuum deposition of metal aluminum on the other surface of the substrate S from the aluminum vapor deposition source 6, and the substrate is wound up with a winding roller 8. In this way, the aluminum porous body excellent in adhesion is inexpensively produced with high speed.

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 a surface of a three-dimensional mesh plastic substrate having an internal communication space is made of metallic aluminum at high speed.

[0002]

2. Description of the Related Art Conventionally, as a method of manufacturing an aluminum porous body having a three-dimensional network structure having an internal communication space, a three-dimensional network plastic substrate having an internal communication space is subjected to a vapor phase plating method, particularly an arc system ion plating. There is known a method in which a metal aluminum layer is formed by performing a vapor deposition treatment of aluminum by a method to cover the surface of the three-dimensional net-like whole lattice extending from the surface portion to the innermost portion of the substrate, and further removing the substrate if necessary. (Japanese Patent Laid-Open No. 6-10077).

[0003]

In the method for producing a porous aluminum body using the above-mentioned arc type ion plating method, the film formation rate is slow and there is a problem in productivity.
The facility cost of the arc type ion plating device is also high.

However, when the vacuum deposition method is used instead of the arc system ion plating method in order to increase the film forming rate and reduce the equipment cost, there remains a problem in the adhesion between the plastic substrate and the metal aluminum layer. .

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

[0006]

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventor has found that in a method for producing an aluminum porous body by vapor phase plating, multi-layer plating by combining different vapor phase plating methods. I focused on the law. Here, the present inventor has found that the adhesiveness in the vapor phase plating method is determined by the film formed first on the substrate, particularly the film properties of the initial several hundred angstroms, and the adhesion of the first layer on the plastic substrate is By selecting the vapor phase plating method that emphasizes adhesion for the coating and selecting the vapor phase plating method that emphasizes the deposition rate for the second layer, it is possible to obtain a metallic aluminum layer with good adhesion at high speed. Successful.

That is, according to the present invention, in a method of forming a metal aluminum layer on a three-dimensional mesh plastic substrate having an internal communication space, an arc type ion plating method or a sputtering method is used for the first layer on the plastic substrate. After forming a metal aluminum layer having a thickness of angstrom to 1 micron, 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 for producing the aluminum porous body in the present invention has a three-dimensional network structure having an internal communication space, and examples thereof include foamed plastic, plastic fiber non-woven fabric and the like. However, of course, it is not limited to these. The foamed plastic may be any as long as it has an open cell structure, but it is preferable that it does not have a cell membrane and is substantially composed only of a skeleton lattice. For example, polyurethane foam from which the cell membrane is removed is preferably used, but open-cell foams such as polystyrene, polyvinyl chloride, polyethylene, polyisocyanurate, polyphenol and polypropylene are also preferably used. As the plastic fiber nonwoven fabric, various plastic fiber nonwoven fabrics 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 aluminum porous body.
Generally, it is preferable that the average pore size is several tens of microns or more. Further, the shape of the substrate is not limited, but its thickness is usually 0.05 to 10 mm. According to the arc type ion plating method, the average pore diameter and the porosity are small, and the thickness is relatively large. Even when the substrate is used, the aluminum layer can be satisfactorily formed on the innermost lattice surface.

According to the present invention, a metal aluminum layer having a thickness of 200 angstroms to 1 micron is formed on the reticulated plastic substrate as a first layer by using an arc type ion plating method or a sputtering method. Here, as compared with the vacuum deposition method of forming a thin film at a thermal speed, since a metal aluminum layer is formed by an arc method ion plating method or a sputtering method of forming a thin film with ions having a kinetic energy larger than the thermal speed, The adhesion between the plastic substrate and the metal aluminum layer is improved.

The arc system ion plating method is a method of evaporating a metal target (cathode) 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 the degree of vacuum is 1 × 10 ⁻³ to 1 × 10 ⁻⁴ Torr, and typically the arc current is about 100 AH and the bias voltage is about 30V. It is possible to form an uneven metallic aluminum layer having a thickness of 200 angstroms to 1 micron. The arc-type ion plating method is used for the first layer to form the uneven metal aluminum layer, so that the surface state of the second layer is also uneven.

On the other hand, the sputtering method is a method in which a high voltage is applied to both electrodes in a closed container containing a working gas to cause glow discharge, and a plating film is formed by a sputtering phenomenon associated with 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, and is not limited to these. The conditions can be appropriately selected even in this sputtering method, but the degree of vacuum is 1 × 10 ⁻³ to 1 × 1.
Sputtering can be performed at 0 ⁻¹ Torr to form a smooth metal aluminum layer having a thickness of 200 Å to 2000 Å. Since a smooth metal aluminum layer is formed in the first layer by using a sputtering method, a metal aluminum layer having a smooth surface state in the second layer is also formed.

In this case, the first metal aluminum layer is formed as an extremely thin layer of 200 angstrom to 1 micron on the plastic substrate. This is a film thickness for improving the adhesion between the plastic substrate and the metal aluminum layer. If the thickness is less than 200 angstroms, the adhesion decreases, and if the metal aluminum layer is thicker than 1 micron, it can be manufactured at high speed. The problem remains.

According to the present invention, a metal aluminum layer having a thickness of 200 angstroms to 1 micron is formed on the first layer on the plastic substrate by using the arc type ion plating method or the sputtering method as described above, and then the second layer is formed.
As the layer, a metal aluminum layer is formed by using a vacuum vapor deposition method.

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

In the present invention, the formation of the metal aluminum layer of the first layer and the metal aluminum layer of the second layer may be carried out by separate apparatuses, but the metal aluminum of the first layer and the metal aluminum of the second layer may be formed. It is recommended that the formation be performed sequentially in the same equipment. That is, the first and second metallic aluminum layers have good adhesiveness between aluminum, and in addition, the arc type ion plating method or the sputtering method and the vacuum deposition 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.

The outline of this continuous device will be described below.
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 vapor deposition method, a sputtering method, and a vacuum vapor deposition method, respectively. (Vacuum chamber), 2 is an aluminum target, 3 is a vacuum pump, 4 is a delivery roller for continuously delivering a plastic substrate, 5 is a roller for holding the plastic substrate, 6 is an aluminum evaporation source, and 7 is a vacuum degree A partition plate 8 is a roller for continuously winding the plastic substrate.

Here, in the apparatus shown in FIG. 1, the front and back surfaces of the three-dimensional net-like plastic sheet (substrate) S sent from the sending roller 4 are first made by arc type ion plating method using metallic aluminum from an aluminum target. After forming the aluminum layer of the layer, first, one surface of the sheet S is vacuum-deposited with metallic aluminum from the aluminum evaporation source 6, and then the sheet S is inverted to vacuum-deposit aluminum on the other surface of the sheet S. It is what makes me. In the apparatus shown in FIG. 2, the first aluminum layer is formed on one surface of the three-dimensional net-like plastic sheet (substrate) S sent from the sending roller 4 by the sputtering method, and then the aluminum is formed on this one surface. Is vacuum-deposited, then 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 aluminum porous body of the present invention can be used as it is, that is, with the aluminum layer formed on the lattice surface of the reticulated plastic substrate, but the reticulated plastic substrate may be removed if necessary. It can be used as an aluminum porous body having a lattice made of only aluminum, that is, an aluminum porous body made of only aluminum having the same lattice mode as the reticulated plastic substrate.

In this case, the method for 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 the plastic substrate by melting or thermal decomposition, a method of dissolving the plastic with an appropriate organic solvent, and the like are adopted.

The aluminum porous body obtained according to the present invention is lightweight, has high corrosion resistance, and is inexpensive and therefore is used in various applications. 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 specifically described below by showing Examples and Comparative Examples, but the present invention is not limited to the following Examples.

[Examples, Comparative Example I] Relationship between vapor-phase plating method and film forming time Polyester non-woven fabric (fiber diameter: about 12 microns, thickness: 0.
A metal aluminum layer having a thickness of 1 mm and a weight of 36 g / m ² of 5 μm was formed under the following film forming conditions, and film forming times were compared. The results are shown in Table 1. Film forming conditions Arc method Ion plating Vacuum degree 1 × 10 ^-4 Torr Arc current 100AH 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 minutes Vacuum deposition method Vacuum degree 8x10 ^-5 Torr Film formation time 4.0 minutes Arc type ion plating method Vacuum degree 1 × 10 ^-4 Torr Discharge current 100AH Film formation time 10.0 minutes

[0025]

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

[Examples, Comparative Example II] Bending test A test piece in which a metallic aluminum layer was formed and coated on a polyester nonwoven fabric under the following film forming conditions was 180
Repeat the bending test 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 method Ion plating Vacuum degree 1 × 10 ^-4 Torr Arc current 100AH 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 minutes 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 type ion plating method Vacuum degree 1 × 10 ⁻⁴ Torr Discharge current 100 AH Film formation time 10.0 minutes

[0027]

[Table 2] [Examples, Comparative Example III] Tape test A test piece obtained by forming a metal aluminum layer on a polyester non-woven fabric under the following film forming conditions and performing coating was subjected to a tape test at 90 degrees with a commercially available cellophane tape, and adhered to the tape. The amount of fibrous deposit and the amount of powder deposit were compared (× 40 magnifying glass). The results are shown in Table 3. Film forming conditions Arc method Ion plating Vacuum degree 1 × 10 ^-4 Torr Arc current 100AH 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 minutes 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 type 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 of Tables 2 and 3 above, it is recognized that the adhesion of the metal aluminum layer is better in the examples of the present invention than in the vacuum deposition method (single layer).

[Application Example] Application Example as Material for Electrode of Lithium Ion Secondary Battery A positive electrode active material (manganese dioxide, cobalt oxide, titanium sulfide, etc.) is applied to an electrode support composed of three types of aluminum porous bodies of the examples. Using a filled positive electrode, a battery made of a non-aqueous electrolyte using an electrode mainly composed of lithium as a negative electrode, and the same positive electrode active material and a conductor (graphite, on the electrode substrate using a conventional aluminum thin plate) Characteristics of a battery made of the same non-aqueous electrolyte as above using a positive electrode coated with a mixture of carbon etc.) and a binder that binds these, and using the same lithium electrode as the above negative electrode (Discharge electric capacity and electric output) were compared. The results are shown in Table 4.

[0030]

[Table 4] As can be seen from the results of Table 4, those using the aluminum porous body as the electrode support of the positive electrode were excellent in all properties. Further, the one according to the present invention showed substantially the same characteristics as the aluminum porous body produced by a single layer only by the arc type ion plating method.

Micrographs of the metallic aluminum layer are shown in FIGS. FIG. 3 is a photomicrograph of a film having a thickness of 5 μm formed by the arc type ion plating method (single layer), FIG. 4 is a photomicrograph of a film having a thickness of 2000 angstrom formed by the sputtering method, and FIG. 5 is an arc type ion plating method (0. 3 micron film) + microscopic photograph formed by vacuum evaporation method (4.7 micron film formation). Fig. 6 shows sputtering method (0.06 micron film formation) + vacuum evaporation method (4.
It is a micrograph formed by 94 micron film formation. As can be seen from FIGS. 3 and 4, in the arc type ion plating method, the uneven metal aluminum layer is formed,
It can be seen that a smooth metal aluminum layer is formed by the sputtering method. Further, as can be seen from FIG. 5 and FIG. 6, when the first layer on the plastic substrate is subjected to the arc ion plating method or the sputtering method, the deposition state of the second layer becomes uneven, or smooth metal aluminum is used. It can be seen that a layer is formed. Note that the magnification of these micrographs is 750 times.

[0032]

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

[Brief description of drawings]

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

FIG. 3 is a photomicrograph of a 5 micron film formed by an arc type ion plating method (single layer).

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

FIG. 5 is a micrograph showing a film formed by an arc system ion plating method (0.3-micron film formation) and a vacuum vapor deposition method (4.7-micron film formation).

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

[Explanation of symbols]

 1 Reactor (Vacuum Chamber) 2 Aluminum Target 3 Vacuum Pump 4 Sending Roller 5 Roller 6 Aluminum Evaporation Source 7 Partition Plate 8 Rolling Roller S Plastic Sheet (Substrate)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshinori Murao 1-5-1, Hirakata-shi, Osaka Uemura Industrial Co., Ltd. Central Research Laboratory

Claims (3)

[Claims] 1. 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.
A method for producing a porous aluminum body, comprising forming a metal aluminum layer having a thickness of angstrom to 1 micron and then forming a metal aluminum layer on the second layer by a vacuum deposition method. 2. An aluminum comprising a three-dimensional mesh lattice of metallic aluminum after forming the first and second metallic aluminum layers on a three-dimensional mesh plastic substrate having an internal communication space and then removing the substrate. The method for producing an aluminum porous body according to claim 1, wherein a porous body is obtained. 3. The method for producing an aluminum porous body according to claim 1 or 2, wherein the arc type ion plating or sputtering and the vacuum vapor deposition are performed in the same vacuum chamber.